About
About CropViewer
A free image viewer and precision cropper for people who work with a lot of image files.
What it is
CropViewer is a browser-based tool for browsing folders of images and cropping them accurately. It was built for game developers — people whose working directories hold hundreds or thousands of sprites, tilesets, UI assets and texture exports — but it is useful to anyone who needs to look through a lot of images and cut exact regions out of them.
It does four things well: it shows you a whole folder quickly, it renders images honestly, it crops in real pixel coordinates, and it exports to the formats that actually get used in art pipelines.
Why it exists
Most image tools fall into one of two camps. Full editors like Photoshop or GIMP can do everything, but opening one to trim 40 pixels off a sprite is slow. Web croppers are quick, but they upload your file to a server, resample it, and hand back something that is not quite what you asked for — and they usually cannot open a TGA, a PSD or a DDS at all.
CropViewer sits in between. It opens instantly, reads your folder directly from disk, and crops to the exact pixel rectangle you specify.
How it works
The app is a static page. When you open a folder, the browser hands it a direct handle to those files through the File System Access API, and everything after that — decoding, thumbnailing, cropping, transforming and encoding — runs in the tab, on your own CPU.
Nothing is uploaded. There is no image server, no temporary storage and no account. After the page has loaded, the app makes no network requests at all, which is why it keeps working with the network disconnected. You can verify this yourself in your browser's Network tab.
Some technical details, for the curious:
- Thumbnails decode on a pool of Web Workers and are cached in memory and in IndexedDB, so a folder you have already browsed reopens instantly.
- The grid is drawn on a single canvas sized to the viewport, so only the cells you can actually see are painted — scrolling a folder of several thousand images stays smooth.
- The crop rectangle is stored in original image pixels, not screen pixels, so zooming and panning never change what gets exported.
- Formats the browser cannot read natively — TGA, HDR, TIFF, PSD, DDS and EXR — are decoded by hand in JavaScript.
History
CropViewer started as a native desktop application written in C++23 and Qt 6, distributed for macOS and Windows. The browser version is a port of that codebase — the same crop engine, the same interaction model, the same dark interface. Since the web version does everything the native one did without requiring an install, the desktop build is no longer distributed.
Cost
CropViewer is free. Every feature and every export format, with no account, no trial period, no watermark and no export limit.