About Cast
Cast converts images between PNG, JPG and WebP right in your browser. Drop in a picture, pick the format you want, and download the result — nothing is uploaded to a server along the way.
Features
- Convert between PNG, JPG and WebP in either direction
- Adjustable quality for JPG and WebP output
- Live preview of the image you've selected
- Shows original vs. converted file size
- Runs entirely in your browser, nothing is uploaded
- No sign-up, no watermark, no daily limit
How to use it
- Drop an image into the box, or click it to browse your files.
- Choose the format you want to convert to: PNG, JPG, or WebP.
- If converting to JPG or WebP, adjust the quality slider if you like.
- Press "Convert," then "Download result" to save the file.
Frequently asked questions
Is my image uploaded anywhere?
No. Cast draws the image onto an in-browser canvas and re-encodes it locally using standard browser APIs. Nothing leaves your device.
Why is there no quality slider for PNG?
PNG is a lossless format, so there's no quality trade-off to adjust — the slider only appears for JPG and WebP, which use compression that can be tuned.
Will converting PNG to JPG lose transparency?
Yes. JPG doesn't support transparent pixels, so any transparent areas will be filled with white when converting from PNG to JPG. WebP does support transparency, so converting to WebP keeps it intact.
Does converting to JPG or WebP reduce quality?
Both are compressed formats, so some detail can be lost depending on the quality setting. Higher quality values keep more detail but produce larger files; lower values shrink the file at the cost of some sharpness.
Is there a file size limit?
There's no fixed cap from the tool itself, but very large images are limited by your browser's available memory rather than by Cast.