And some probably look crappy.
This cheat sheet helps you nail down the right resolution.
The guide shows the resolution your pictures are displayed at.
sRGB colorspace
Profile Photo
Must be at least 180 x 180 pixels.
Image uploads of 2048 x 2048 pixels.
Shared Image displayed on Timeline
Longest edge is scaled to display 504 pixels.
The author promises that they’ll update the post if any of these sites adjust their standards.
Which, of course, is as inevitable as the tide.
A Creative’s Quick Guide to Social Media Image Sizes| Design Instruct
