Compress a JPEG

Make a JPEG smaller, without changing anything else about it.

A photograph straight off a phone is often two or three times larger than it needs to be for anything except printing. Re-encoding it at a sensible quality typically halves the file with no visible change on a screen.

Two things to know. A JPEG that has already been squeezed hard will barely shrink further — there is nothing left to give. And each compression pass is permanent, so always start from the best copy you have rather than compressing a compressed file.

There is no single correct quality number. Try eighty, look at the result at full size rather than as a thumbnail, and only then decide whether to keep it.