What DPI means for form photos, and why it doesn’t change the KB
DPI (dots per inch) tells a printer how large to print an image. A 600 × 600 pixel photo at 300 DPI prints at 2 × 2 inches, and the same file at 150 DPI prints at 4 × 4 inches. The pixels and the file size stay the same.
Why forms ask for it
Some portals read the DPI value from the file and reject anything other than, say, 200 or 300. Most phone photos say 72 DPI, even though they have plenty of pixels.
How to fix it
- Open Change DPI, or Convert image to 300 DPI.
- Choose your JPG or PNG and pick the DPI the form asks for.
- Download. Only the DPI value in the file changes, so the picture and the KB stay exactly as they were.
Pixels from cm and DPI
If a form gives a print size such as 3.5 × 4.5 cm, use cm to pixels to get the pixel size at its DPI, then resize to those pixels.