View and export
JPEG 2000 images on Windows
JPEG 2000 Explorer adds native JP2 support to Windows Explorer — thumbnails, previews, and file properties — plus a dedicated app for viewing, zooming, inspecting metadata, and exporting your JPEG 2000 images to PNG, JPEG, PDF, and more. It can also register JPEG 2000 across Windows for every user (administrator required), so thumbnails, previews, and file properties show for everyone and other apps can open these files too.
Installation
JPEG 2000 Explorer is distributed through the Microsoft Store as a single package that installs both the desktop app and the Windows Explorer shell extensions.
No configuration needed. After installation, JPEG 2000 thumbnails, the preview pane, and file properties work automatically in Windows Explorer. Just navigate to a folder containing JP2 files.
What gets installed
JPEG 2000 Explorer App
A desktop app for opening, viewing, and exporting JPEG 2000 images. Accessible from the Start menu.
Shell Extensions
Background components that power thumbnails, the preview pane, and file properties in Windows Explorer. These run automatically — no action needed.
An optional, machine-wide Shell Integration (administrator required) registers JP2 thumbnails, previews, file properties, and a decoder for everyone on the PC, and makes them appear even when another app is your default for .jp2. Turn it on from Settings → Shell Integration — see Shell Integration.
The Interface
JPEG 2000 Explorer has a simple left-hand navigation. You can open an image by clicking Open a JPEG 2000 file, dragging a file onto the window, or launching it from Windows Explorer.
Opening a file is required before the Images and Export pages show anything. The Home and Images pages always offer an Open a JPEG 2000 file button to get started.
Opening a file
There are three ways to open an image in the app:
- Click Open a JPEG 2000 file on the Home or Images page and pick a file from the browser dialog.
- Drag and drop a JP2 file from Windows Explorer directly onto the JPEG 2000 Explorer window.
- In Windows Explorer, right-click a JPEG 2000 file and choose Open with → JPEG 2000 Explorer. The app opens and goes straight to the Images page.
Single instance: the app runs as a single window. If you open it from Explorer while it's already open, the existing window is brought to the front and the new image is loaded — you won't get a second window.
Windows Explorer Integration
Once JPEG 2000 Explorer is installed, Windows Explorer gains three new capabilities for JP2 files — no extra steps required.
Thumbnails
JPEG 2000 files display their actual image content as a thumbnail in Explorer's icon view, so you can recognise a picture without opening it.
Preview Pane
Select a JP2 file and press Alt+P (or use View → Preview Pane) to see a live, zoomable preview directly inside Explorer — no app launch needed.
File Properties
Image dimensions, bit depth, colour space, and embedded metadata appear in Explorer's Details pane, tooltips, and the file's Properties → Details tab.
Using the Preview Pane
The preview pane renders your image at full quality. Here's what you can do inside it:
| Action | How |
|---|---|
| Zoom in / out | Hold Ctrl and scroll the mouse wheel |
| Scroll the image | Use the scroll bar or scroll the mouse wheel |
| Change background | Right-click the preview for a list of background colours |
How thumbnails & previews stay fast
JPEG 2000 stores an image at multiple resolution levels. Thumbnails and the preview pane take advantage of that: they decode only the resolution level Windows actually asked for, rather than the full-resolution image. That's why even a very large scene (hundreds of megapixels) still produces a thumbnail quickly. Zooming into the preview decodes just the visible region at higher detail — see Limitations for how this affects performance on big files.
Unlike some formats, a JPEG 2000 file usually doesn't carry a separate embedded thumbnail — the thumbnail you see in Explorer is generated on demand by decoding a low resolution level of the image itself.
Thumbnails look out of date? Windows caches thumbnails. After changing related settings, use Settings → Reset Thumbnails to make Windows Explorer rebuild its thumbnail cache. You can also clear it with Windows' built-in Disk Cleanup tool: press Win+R, run cleanmgr, tick Thumbnails, and click OK.
Viewing Images
The Images page is the app's main viewer. It renders your JPEG 2000 image at high quality and lets you zoom and inspect it in detail. The image opens fitted to the window.
Zoom & fit
Use the Zoom dropdown at the top of the page to jump to a preset zoom level, or type a custom percentage. While looking at the image, hold Ctrl and scroll the mouse wheel to zoom smoothly — a small indicator shows the current zoom level.
Three fit buttons let you frame the image instantly:
| Button | What it does |
|---|---|
| Fit | Scales the whole image to fit inside the window |
| Fit width | Scales so the image's width fills the window |
| Fit height | Scales so the image's height fills the window |
Large images & progressive detail
The viewer is built for JPEG 2000's very large images. It opens at a reduced resolution that fits the window, then decodes more detail for the region you're looking at as you zoom in. A progress bar appears while a bigger decode is in flight. This keeps opening and panning responsive even for multi-gigabyte scenes — the trade-off is that the first moments after a deep zoom on a huge file may take a little time. See Limitations.
Colour management
If your image carries an embedded ICC colour profile, JPEG 2000 Explorer can honour it so colours appear as intended. This is controlled by Settings → Honour colour profile. When it's off (or no profile is present), the image is shown as standard sRGB / greyscale.
Image Information & Metadata
JPEG 2000 Explorer reads the technical facts and the embedded metadata stored inside a JP2 file, and surfaces them both inside the app and — with Shell Integration installed — in Windows Explorer.
In the app
On the Images page, click the information (ⓘ) button to open a summary of the open image. Depending on what the file contains, this can include:
| Property | Description |
|---|---|
| Dimensions | Image width and height in pixels |
| Components & bit depth | Number of channels and bits per component |
| Colour space | sRGB, greyscale, and whether an ICC profile is embedded |
| Resolution / DPI | Capture or display resolution when present |
| Title, author, description… | XMP / Dublin Core fields embedded in the file |
| Comments | Text comments stored in the codestream |
In Windows Explorer
The same information is exposed to Windows through a property handler, so JPEG 2000 files behave like other picture types: you can add columns such as Dimensions, Title, or Authors in Explorer's Details view, read them in the info tooltip, and see them in the file's Properties → Details tab.
The richer set of Explorer property columns (title, authors, dimensions, and more) is provided by the Shell Integration. If those columns look empty, make sure it's installed in Settings.
Exporting
The Export page converts your JPEG 2000 image into a widely-supported format — a raster image (PNG, JPEG, and more) or PDF. You can export several sizes in a single click, which is handy for producing web, app, or print assets.
Export settings
| Setting | Description |
|---|---|
| Output folder | Where exported files are saved. Click Browse to pick a folder, or Open folder to view the current destination in Explorer. |
| File name template | Controls how exported files are named, using tokens like {name} and {size} — see the token reference. A live sample shows what the file name will look like. |
| Image format | The output format: PNG, JPEG, BMP, TIFF, PDF, and others registered on your system. See the full list. |
| Overwrite | When on, existing files with the same name are overwritten. When off, existing files are skipped with a warning. |
Export sizes
Each row in the size list produces one output file. The number is a pixel size: the image is scaled so its longest side is that many pixels, and the other dimension scales proportionally. Default sizes are 256, 512, 1024, and 2048 pixels, and any size up to 16384 is allowed.
Add size
Adds the next standard size (256 → 512 → 1024 → 2048). Once all standard sizes are present, it doubles the largest existing size.
Clear all / Remove
Click Clear all to remove every size, or Remove next to a single row to delete just that one.
You can also edit a size number directly in any row. Sizes are always sorted smallest to largest.
Running an export
- Open an image on the Images page first.
- Go to the Export page.
- Set your output folder, format, and sizes.
- Click the Export button. A notification confirms how many files were saved. A progress overlay appears if the export takes more than a moment.
The Export button is disabled if the output folder is invalid, the file name template is missing {size}, no sizes are listed, or no format is selected. A message in red explains what needs fixing.
Better Shell Integration (all users, administrator required)
JPEG 2000 Explorer can register JPEG 2000 with Windows itself, for every user on the PC. This turns on JP2 thumbnails, the preview pane, and file properties in File Explorer, plus a system-wide decoder so other Windows apps can open JPEG 2000 files. Because it changes the machine, Windows asks for administrator approval when you turn it on or off.
This is optional. The JPEG 2000 Explorer app itself works without it. Turn it on when you want JP2 thumbnails, previews, and properties in File Explorer for everyone, and other apps to open JPEG 2000 files.
It works even when another app is your default. If you open JP2 files in another program (say a graphics editor) and keep it as your default, JPEG 2000 Explorer still supplies the thumbnails, previews, and properties. Windows uses them as a fall-through when your chosen app doesn't provide its own, and your default app for double-click stays exactly as you set it.
Install, update, uninstall
Everything is done from Settings → Shell Integration. The card shows the current status and the matching action button, and each action prompts for administrator approval (a standard Windows UAC dialog).
| Status | Meaning | Button |
|---|---|---|
| Not installed | JPEG 2000 is not registered with Windows on this PC. | Install |
| Installed | Registered for all users and current. | Reinstall / Uninstall |
| Installed, update available | A newer build ships with this app version than the one registered. | Update / Uninstall |
Listed in Windows. It also appears in Settings → Apps → Installed apps as "JPEG 2000 Explorer Shell Integration", and can be removed there at any time, independently of the JPEG 2000 Explorer app.
Give it a minute. After you install it, thumbnails can take a while to appear. Windows caches how it resolves thumbnail handlers, separately from the picture cache, so a folder may show the old icons for a bit. Wait a little, or run Reset Thumbnails (see Settings) and press F5.
Why it needs administrator, and why updates are separate
Windows resolves thumbnail, preview, and codec handlers from a machine-wide location that only an administrator can write, and a system-wide decoder must live there too. So this integration installs for all users and asks for approval. It's copied to a stable per-machine folder, so it keeps working across app updates and even if the Store app is removed. Because it lives outside the app package it doesn't update itself, so a newer app version flags update available and one click refreshes it.
Not every app can use the decoder. Some modern Microsoft Store / packaged apps — notably Windows Photos and Paint — rely on their own built-in list of supported formats instead of asking Windows, so they will not pick up a third-party JPEG 2000 decoder. Classic desktop apps that decode through Windows Imaging Component do benefit, as do File Explorer's thumbnails, previews, and properties.
Some apps use the decoder through a plugin. A few programs don't call Windows Imaging Component directly but can be extended to. Paint.NET, for example, can use such a plugin to route its open/save dialog through installed codecs.
Recent Files
The Recent files page keeps a list of images you've opened before, so you can jump back to them quickly.
| Action | Description |
|---|---|
| Click a file link | Opens that image in the viewer. |
| Clear recent files | Removes all entries from the history. You'll be asked to confirm if the list isn't empty. |
| Remove missing files | Scans the list and removes entries for files that have been deleted or moved. |
You can turn recent-file history off entirely in Settings if you prefer not to track recently opened images.
Settings
The Settings page groups the app's options. Most viewing and export choices are made in context (zoom and background on the Images page, options on the Export page).
Appearance & behavior
| Setting | Options | Description |
|---|---|---|
| App theme | Light Dark System | Controls the app's colour scheme. System follows your Windows light/dark mode. |
| Save recent files | On / Off | When off, the app stops recording recently opened images. If you turn it off with entries present, you're asked whether to clear or keep them. |
Rendering
| Setting | Options | Description |
|---|---|---|
| Honour colour profile | On / Off | When on, an embedded ICC profile is applied so colours look as intended. When off, images are shown as standard sRGB / greyscale. |
Thumbnails
| Setting | Description |
|---|---|
| Reset thumbnails | Asks Windows Explorer to rebuild its thumbnail cache so thumbnail changes take effect. You'll be asked to confirm before it runs. |
Windows imaging integration
Install, update, or remove the machine-wide shell integration: JP2 thumbnails, previews, file properties, and a decoder for all users. Each action needs administrator approval. Covered in full under Shell Integration.
The About section shows the app version and a link to display detailed System Information — useful when reporting an issue. Your last-used export folder, file name template, image format, and sizes are remembered automatically between sessions.
Supported Formats
Input — JPEG 2000
JPEG 2000 Explorer opens the JPEG 2000 family: the JP2 container and raw codestreams.
Export
Raster exports cover the image formats registered on your Windows system; the most common are shown below. PDF wraps the image in a document page. A green dot marks formats that support transparency; a blue dot marks document/vector output.
* HEIC/HEIF requires the HEIF Image Extensions package from the Microsoft Store, or another codec that registers HEIC/HEIF support. If it's not installed, the format won't appear in the list.
Best all-round choice: PNG keeps full quality and transparency and is supported everywhere. Use JPEG for smaller photographic files, or PDF when you want a document you can share and print.
JPEG 2000 is a read-only (input) format here. JPEG 2000 Explorer decodes JP2 files — it does not create or re-save them. To keep an image, export it to one of the formats above (see Limitations).
File Name Tokens
Customise how exported files are named using these tokens in the File name template field. Tokens are case-insensitive. Write {{ if you need a literal brace.
Example template: {name}_{size} produces files like scan_256.png, scan_512.png, and scan_1024.png. The {size} token is always required so that each size gets a distinct file name.
Keyboard Shortcuts
Quick actions available in the JPEG 2000 Explorer app and in the Windows Explorer preview pane.
In the JPEG 2000 Explorer app
In the Windows Explorer preview pane
Window & navigation
Limitations
JPEG 2000 Explorer is a fast, accurate viewer, converter, and decoder — not an image editor or a JPEG 2000 encoder. Knowing what it focuses on helps set expectations.
Decode & export only
You can open, inspect, and export JPEG 2000 images, but you cannot edit them or save changes back to JP2. The app decodes JPEG 2000; it does not encode it — there is no "Save as JP2". To keep a result, export it to PNG, JPEG, PDF, or another supported format. Your original files are never modified.
Very large images & memory
JPEG 2000 is designed for very large pictures, and the app embraces that. Thumbnails, previews, and the viewer decode at a reduced resolution level and can bound their memory use automatically, so even scenes of hundreds of megapixels — or files that are gigabytes in size — will open. What changes with size is cost: a full-resolution decode of a huge image needs time and memory in proportion to the pixels involved, so the biggest images are best viewed at fitted zoom and exported at a chosen size rather than decoded at 100% all at once.
Performance: big files versus zoom
At a fitted or low zoom, the viewer shows a reduced-resolution version of the image almost instantly. As you zoom in, it decodes the visible region at a higher resolution level (a "windowed" decode), and a progress bar appears while that work happens. This is expected and by design: detail is fetched on demand instead of decoding the entire full-resolution image up front. On very large files a deep zoom can therefore take a moment to sharpen — panning around at that zoom then stays responsive.
Decoding, markers & compatibility
The decoder covers the common JPEG 2000 feature set — both wavelet transforms, tiling, quality layers, all resolution levels, colour transforms, embedded ICC profiles, and the JP2 box metadata described in this guide. Files produced by mainstream tools decode faithfully. However, some rare, exotic, or non-conformant constructs — unusual marker combinations, uncommon colour configurations, or files that are truncated or damaged — may not decode, or may render only partially.
When a file can't be decoded, the app tells you rather than showing a wrong or silently blank image:
| Where | What you see |
|---|---|
| In the viewer | The Images page replaces the picture with the message "This image can't be displayed. It may be corrupt or use an unsupported feature. See the document properties (ⓘ) for details." |
| In the ⓘ info flyout | The information (ⓘ) button on the Images page shows a Status: Cannot be decoded line plus an Error line with the decoder's own message — useful when reporting a broken or unsupported file. This also appears when the header reads fine but the pixels fail to decode. |
The same underlying check runs when Explorer asks for a thumbnail or preview, so a file that can't be decoded simply falls back to the generic icon rather than showing a broken thumbnail.
Colour & fidelity
Embedded ICC colour profiles are honoured when Honour colour profile is on; otherwise images are treated as sRGB / greyscale. The viewer, preview, and exports are resolution-independent, so images stay crisp on high-DPI / scaled displays (125%, 150%, 200%, and beyond), and exports are pixel-exact at the size you choose.
Tips & Tricks
Producing web / app assets in one pass
- Open your JPEG 2000 image and go to the Export page.
- Choose PNG (or JPEG for photos) and set the sizes you need — the defaults 256 / 512 / 1024 / 2048 cover most cases.
- Use a template such as
{name}_{size}so files are namedphoto_256.png,photo_512.png, and so on. - Click Export — every size lands in your output folder in a single run.
Opening a JP2 in another app
Want a different program to open JPEG 2000 files? Turn on Shell Integration from Settings (administrator required). Classic desktop apps that read images through Windows Imaging Component will then recognise .jp2 files. Note that some Store apps (Photos, Paint) use their own format list and won't — see Shell Integration.
Browsing a folder full of large JP2s
Thumbnails are generated from a low resolution level of each file, so even folders of very large images stay browsable. If thumbnails ever look stale after changing settings, run Reset Thumbnails in Settings.
Thumbnails or previews don't show (another app is the default)
Windows lets only one app provide thumbnails and the preview pane for a given file type: the app currently set as the default for that type. If another installed program also handles JPEG 2000 files and is set as the default, Windows uses its thumbnails and preview instead, so JPEG 2000 Explorer's may not appear.
- Open Windows Settings → Apps → Default apps.
- Find and click JPEG 2000 Explorer in the list (type its name in the search box if needed).
- For each JPEG 2000 extension (
.jp2,.j2k,.j2c,.jpc,.jpt,.jph), click the file type and choose JPEG 2000 Explorer as the default.
Thumbnails and previews always follow the file type's default app, so this works in reverse too: if you prefer another app for certain formats, leave those set to it. After changing the default, run Settings → Reset Thumbnails if Explorer still shows old cached thumbnails.
Preview stays blank for files downloaded from the internet
Starting with Windows 11 25H2, Microsoft blocks the File Explorer preview pane for files that carry the "Mark of the Web" — files downloaded from the internet, or coming from a location Windows considers unsecured. This affects every file type, not just JPEG 2000 images, and it is a Windows security decision: there is nothing JPEG 2000 Explorer can do at its level to override it.
How to restore the preview: right-click the file → Properties, tick Unblock at the bottom of the General tab, then click OK. To clear many files at once, PowerShell's Unblock-File cmdlet does the same in bulk.
Microsoft has acknowledged this behaviour. For the full explanation and more ways to re-enable previews, see this Windows Latest article — in particular its "How to unblock previews in File Explorer" chapter.
Dark mode
JPEG 2000 Explorer follows your Windows theme by default. For a fixed look, choose Light or Dark explicitly in Settings.
If JPEG 2000 Explorer has earned a spot in your workflow, a quick rating on the Microsoft Store helps other people discover it, and it means a lot to our small team. It takes less than a minute.
★ Rate JPEG 2000 Explorer on the Microsoft Store