Convert Image

No. Decoding and re-encoding both happen locally, using the browser's canvas for JPG and PNG and small WebAssembly modules for WebP and AVIF. Your photos are never transmitted anywhere during the conversion.

Choose JPG for photos when you need maximum compatibility with older apps and printers. Choose PNG when the image needs a transparent background, like a logo or an icon. WebP and AVIF produce smaller files than JPG at similar quality, with AVIF usually the smallest of the four, though a few older apps still don't open it.

Yes. HEIC and HEIF files are decoded on your device using the heic-to library before being re-encoded into whichever format you picked. There's no separate HEIC converter step required — just drop the photos in like any other image.

It controls how much compression is applied when encoding JPG, WebP, or AVIF — a lower value trims more file size at the cost of some sharpness. PNG is a lossless format, so the slider has no effect when PNG is selected as the output.

JPG has no way to represent transparent pixels, so any transparent area is filled with a white background before the image is saved. If you need to keep transparency, convert to PNG or WebP instead, both of which support it.

They solve different problems. Convert Image changes the file type — JPG to WebP, HEIC to PNG, and so on — while Compress Image keeps the same format but re-encodes it at a smaller size. Combine them by converting first, then compressing the result if you need both a new format and a smaller file.

WebP and AVIF encoding runs through WebAssembly, which is slightly slower than the browser's built-in JPG and PNG encoder, especially on large or high-resolution photos. Older browsers that lack native AVIF decoding also fall back to a slower software decoder, which adds a bit more time.