PAN Card photo requirements
The PAN Card form checks the file type, pixel size and file size in KB before it accepts an upload. 108pdf applies all three in one step, then shows the final size with a clear pass or fail check.
The PAN portal reads the DPI stored inside the JPG. Many resizers leave it at 72 DPI and the upload fails. 108pdf writes 300 DPI into the file header for you.
Why uploads get rejected
The most common reasons are a file above the KB limit, a file below the minimum KB, the wrong format (PNG or HEIC instead of JPG), and a face that is too small or too dark. The size and format are handled for you here; for the photo itself, use daylight and a plain wall.