Crop Image to Square

The specific failure mode of a square profile picture is the top of the head or the chin getting clipped, because most source photos are not composed with a square crop in mind and the face sits somewhere other than dead center of a square region. Leaving a small margin above the head rather than cropping tight to the hairline gives room for the circular mask most platforms apply on top of the square image, which crops a further few percent off each corner and would otherwise clip a tight crop even more.

For a photo with more than one person, centering the crop on the midpoint between faces rather than on either individual usually produces a more balanced result than centering on whichever face happens to be more prominent in the original framing.

Nearly every platform that requests a square avatar then displays it inside a circular mask rather than the square itself — LinkedIn, Slack, most forum software, and the majority of comment systems all crop the corners off a square upload automatically. This means detail placed in the corners of a square selection is routinely lost regardless of what the upload preview shows, and the safest composition keeps anything important — a face, a logo, text — within the circle that would be inscribed inside the square, roughly 15% in from each edge.