Jon Loomer has created a standout guide of image sizes in use on Facebook that every marketing person needs!
[Update: This has been updated to reflect the new Page design and Timeline changes of spring 2014. Update and current as of April 8, 2014]
This is simply the best resource we’ve seen compiled on Facebook’s dimensions and you need to bookmark it! It give you the Facebook display size and recommended upload size.
Jon is doing great things training Facebook marketers on Facebook’s Power Editor for Ads setup (very important in 2014) and also Facebook Insights (the stats you need to know).
Bonus resource: I was privileged to host Jon on my podcast for a Facebook Insights, marketing, and Graph Search discussion that you can listen and learn from here: MikeGingerich.com/jon-loomer.