Convert an image when the format you have isn't the one you need. The iPhone saves photos as HEIC, which many websites and Windows PCs won't open. A web page gives you WebP or AVIF images that an older app can't edit. A form accepts only JPG. A designer wants PNG. Drop the images, pick the format and download them converted.
It reads HEIC, JPG, PNG, WebP, GIF, AVIF, BMP, TIFF and anything else your browser can open, and saves to JPG, PNG or WebP. Three settings cover most needs. Format: JPG for photos that have to open anywhere, PNG for screenshots and graphics, WebP for smaller files on the web or when you need transparency in a lighter file. Quality: high, medium for a smaller file, or smallest file. Size: original, or a long side of up to 2560, 1600 or 1080 pixels.
The conversion runs in your browser, so nothing is uploaded and it is quick: a JPG takes under half a second and a 12-megapixel HEIC about 3 seconds. Photos are turned the right way using the rotation saved by the camera, and HEIC colors are kept. You can drop a whole batch and download everything as one archive.
A few things worth knowing. A photo saved as PNG gets bigger, not smaller, because PNG keeps every pixel exactly; that's the format, not a bug. Converting a JPG to PNG doesn't bring back quality that the JPG already lost. Transparency survives in PNG and WebP but not in JPG, where the background turns solid. And the output can't be a PDF yet.
Two pages run the same converter with settings already chosen for a common job. Compress image makes JPGs of medium quality with the long side up to 2560 pixels, for email and upload limits. HEIC to JPG turns iPhone photos into high-quality JPGs at their original size.
If what you need is a cut-out rather than a new format, the background remover gives you a PNG with a transparent background.