Pick PNG when an iPhone photo is going into an editor, not into a message. PNG stores the decoded pixels exactly, so nothing more is lost, and the bytes add up: a 134 KB HEIC photo of a coffee cup became a 531 KB PNG, four times the size, with not one pixel changed. The first photo took about 0.4 seconds while the decoder loaded; the next ones took under a tenth of a second each.
The same two photos as JPG and as PNG
| Photo | HEIC | As JPG | As PNG |
|---|---|---|---|
| Coffee cup, 600×400 | 134 KB | 53 KB | 531 KB |
| Cat, 451×300 | 67.3 KB | 27.8 KB | 293 KB |
For a photo you are going to send, post or upload, we’d take the JPG: it is a tenth of the size, and at quality 85 the difference is hard to spot. PNG pays for its size when the photo is one step in a longer job. If you will crop it, mark it up, drop it into a design file and save it several times over, every JPG save compresses it again, while a PNG save does not. Some templates and forms also simply ask for PNG.
What carries over
The colors do. The cat photo had a color profile embedded, and the PNG received the same profile. iPhone photos that are tagged as Display P3 get a Display P3 profile written into the PNG, so a color-managed viewer shows the colors the phone showed. Rotation stored in the HEIC is applied, so the PNG is upright.
Some things do not. The date, location and camera details are left out (see the questions below). An iPhone HDR photo keeps its standard picture, without the extra brightness HDR screens can show. A Live Photo gives you the still image only, without its video.
On a Mac, without this page
Open the photo in Preview, choose File → Export, and set Format to PNG. For a stack of photos, select them all in Preview’s sidebar and use File → Export Selected Images.
If a PNG turns out too large for where it is going, Compress image can squeeze it a little without changing a pixel, or Resize image can reduce its dimensions.