Help & How-To
Short, practical guides. Everything runs locally in your browser — no uploads.
Getting started
- Add images — drag and drop files onto the page, click the drop zone, or paste from the clipboard.
- Choose an output format — JPG, PNG or WebP (AVIF in supported browsers).
- Adjust options — quality, and under Advanced settings: resize and the background colour for JPG.
- Convert — results appear in the list. Download them individually or use Download all as ZIP.
Batch conversion & ZIP
Select or drop multiple files at once. You can add up to 50 files per session, each up to 50 MB. Once more than one file is converted, the Download all as ZIP button appears and packages every result into a single archive.
Quality
The quality slider (1–100) controls lossy compression for JPG and WebP. Lower values give smaller files, higher values keep more detail. Around 80 is a good balance for the web; 90–95 is better for printing or archiving. PNG ignores the slider because it is lossless.
Resize
Enable Resize under Advanced settings and enter a maximum width and/or height in pixels. Images are scaled down proportionally; they are never stretched or cropped, and smaller images are not enlarged.
Transparency & JPG background
PNG and WebP keep transparency. JPG cannot store transparency, so transparent areas are filled with a solid colour. Under Advanced settings → Background for JPG you can pick white, black, or a custom colour before converting.
Metadata & privacy
FormatFlash re-encodes every image locally, which removes EXIF, GPS and other embedded metadata. Image dimensions are preserved. Because the whole process happens in your browser, your files are never uploaded, stored, or inspected on a server. See the privacy policy for details.
Using FormatFlash on mobile
On iPhone and Android, tap the drop zone to open your photo library and pick one or more images. On many devices you can also share photos directly to the browser. Everything is processed on the device, so it works even on a slow connection.
Keyboard shortcuts
| Keys | Action |
|---|---|
| Ctrl/Cmd + O | Choose files to convert |
| Ctrl/Cmd + V | Paste an image from the clipboard |
| Ctrl/Cmd + Enter | Start conversion |
| Ctrl/Cmd + K | Open the site search |
| / | Open search (when not typing) |
| Esc | Close search or dialogs |
| Enter / Space | Open the drop zone when it is focused |
| ↑ / ↓ | Move through search results |
Troubleshooting
“This image could not be loaded.”
The file may be corrupted, or it uses a format your browser cannot decode. Try opening it in an image viewer first and re-saving it, or convert it to JPG/PNG in another tool.
“This HEIC/HEIF file could not be decoded.”
HEIC/HEIF decoding uses a bundled library. Some very new or unusual HEIC variants may not decode. Re-saving the photo as JPG on the original device usually solves it.
“This image is too large for your browser to process.”
Very large images are limited by the memory available to your browser tab. Try closing other tabs, or resize the image to a smaller maximum width first.
Conversion seems stuck
Large batches take longer. Keep the tab open and in the foreground. If it does not finish, reload the page and try fewer files at once.
Accessibility
The converter is usable with a keyboard and screen readers: the drop zone can be focused and opened with Enter, progress is announced, and the search palette is fully keyboard-navigable. If you hit a barrier, please let us know.