It changes the wrapper.
A file format is the way the same underlying media is packaged and encoded. Converting changes compatibility and storage behaviour more than it changes the subject itself.
Image & Photo
Change this image to another format.
Convert to JPG, PNG or WebP without uploading it.
1 Choose2 Adjust3 Preview & download
Useful to know
Four things worth knowing.
Conversion is not enhancement.
Conversion is not enhancement. Re-encoding a poor source cannot restore missing detail, and some formats lose transparency, animation or metadata.
Check what the format dropped.
Open the finished image at normal size and check crop, sharpness, dimensions and file size.
Choose for what happens next.
Choose the format for what happens next: JPG for ordinary photos, PNG when transparency matters, WebP/AVIF for web delivery, and keep the source if you may edit again.