Supported formats
Files are recognized by their extension, case-insensitively (IMG_0001.CR3 and img_0001.cr3 are both listed). Files with any other extension are ignored.
RAW
| Brand | Extensions |
|---|---|
| Canon | cr2 cr3 |
| Fujifilm | raf |
| Leica | rwl |
| Nikon | nef nrw |
| Sony | arw srf sr2 |
| Cross-brand | dng, Adobe’s open RAW format, used by many brands |
Canon’s older CRW format is not supported: the RAW library used here cannot extract its embedded preview.
Standard images
jpg jpeg png tif tiff bmp webp
How images are displayed
RAW files are displayed from the JPEG previews the camera embedded in them; nothing is demosaiced. Reading an embedded JPEG takes a fraction of the time a RAW development would, which is what makes browsing a RAW shoot fast.
- CR3 (Canon). A CR3 file holds several JPEG renditions of the shot. Thumbnails use the 1620×1080 preview, which decodes in a few milliseconds; the viewer uses the full-size embedded JPEG.
- Other RAW formats. The embedded preview is extracted with rawler and used for both the thumbnail and the viewer. Its resolution depends on the camera: often full size, sometimes smaller.
- Standard images are decoded directly.
The orientation recorded by the camera (EXIF orientation) is applied, so portrait shots are shown upright. Images are also reduced to the size the screen needs: thumbnails to the size of their cell on screen (between 256 and 1024 pixels on the long edge), the viewer image to the resolution of your monitor (at most 4096 pixels).
Keep in mind what an embedded preview is: the camera’s own JPEG rendering of the shot, with its picture style and white balance as set at capture time. That is what you see in Image Toolkit, not a neutral development of the RAW data, and the level of detail is that of the preview the camera chose to embed.
When a file cannot be displayed
A file that cannot be read or decoded gets a warning sign (⚠) in the grid instead of a thumbnail; hover it to read the error message. The viewer shows the message in place of the image. The rest of the folder is not affected.
Since RAW files are only shown through their embedded preview, a RAW file without a usable embedded JPEG cannot be displayed. For example, CR3 files shot with Canon’s HDR PQ mode turned on carry HEIF previews instead of JPEG ones, which Image Toolkit does not decode.