How to compress a JPEG to 100 KB
- Tap Choose a JPEG and pick the .jpg or .jpeg file.
- The target is already 100 KB. Tap Compress to 100 KB.
- Check the size and the preview, then save.
Every JPEG save costs a little, and it never comes back
JPEG is lossy, which means saving one discards detail permanently. Compressing a JPEG that was already compressed does it a second time, on top of the damage from the first — this is generation loss, and it is why a picture that has been forwarded through five chat apps looks the way it does.
One extra pass to meet an upload limit is not something you will see. What you should avoid is doing it repeatedly: compress from the largest original you still have rather than from the version you compressed yesterday, and keep the original in case a different form wants a different number.
Why this page will not hand you a PNG
Converting a photograph to PNG makes it larger, often several times over, because PNG stores every pixel exactly. On the generic compress page the tool is free to change format if that is the only way to hit a target. Here it is not: you came for a JPEG and the output is a JPEG, even in the rare case where that costs a little quality.