Do you know where you put your notes on social media app image sizes? Dredging for this information steals time. Even more confusing is that the recommended dimensions frequently change. I’ve learned that it helps to create a large square image that can be resized for several social media networks. Facebook, in particular, is a moving target; we’re now better off using the 16:9 wide-screen or “letterbox” ratio at 1920×1080 pixels, without text near top and bottom to get a good crop on desktop and fill the screen on smartphones and tablets.
Updated for 2018, these cheat-sheet pages can help:
Social Media Image Sizes Guide by Sprout Social – Always up-to-date, with concise guides and helpful links.
Social Media Image Sizes by Go Daddy Garage – Solid tips about workflow.
Recommended 2018 Facebook Profile Picture Size and More by The Digerati – Brilliant explanation.