How to convert JPG to PNG
- Tap Choose a JPG and pick one file, or up to thirty.
- Tap Convert to PNG.
- Save the result — expect it to be considerably larger than the original.
PNG will not undo what JPEG already did
JPEG discards detail when it saves. Once discarded it is gone, and no later format can work out what it was. Converting to PNG stores the damaged pixels perfectly instead of storing them approximately, which means the result looks exactly like the JPG it came from and takes several times the space.
That is still worth doing when the next step in your workflow needs PNG, or when you are about to edit the image repeatedly — every JPEG save costs a little more quality, and PNG saves cost nothing. It is not worth doing to a photo library.
Expect the file to grow
A three megabyte JPEG photograph commonly becomes fifteen or twenty megabytes as a PNG. PNG compresses by finding repetition, and a photograph — grain, gradients, texture — has very little. Flat graphics go the other way and can shrink, which is why PNG is the right format for screenshots and logos and the wrong one for holiday photographs.
If you need PNG and also need a size limit, convert here first and then reduce the pixel dimensions — squeezing a PNG by quality is not a thing the format supports.