I can not tell you how many times I have been searching the web looking for the correct size of the Google+ profile image, or the optimal size to make aTwitter background. For myself I do not do this enough to remember from time to time.
LunaMetrics has just published a great infographic detailing all the specs you need to customize graphics for all the major social media platforms.
Be sure to save this locally… you will need it… at least until Facebook updates again ; )
Designed by LunaMetrics