The photo must be in square aspect ratio (= same width as height).
The photo must have a minimal size of 600x600 pixels.
The photo file must not exceed a file size of 240 kilobytes.
The photo file must have a file size of at least 54 kilobytes.
The photo must be saved in JPEG file format.
The photo must be in True Color (no black/white or similar).
The background of the photo must be white