1. Facebook
1.1. Timeline Cover
1.1.1. Size
1.1.1.1. 851x315px
1.1.2. Best Practices
1.1.2.1. New node
1.1.2.1.1. New node
1.1.2.2. New node
1.1.2.3. New node
1.1.2.4. New node
1.1.3. Awesome timeline covers
1.1.3.1. http://www.hongkiat.com/blog/creative-facebook-timeline-covers/
1.1.3.2. http://pmorganbrown.com/2012/03/12/46-best-facebook-timeline-cover-images-gallery/
1.2. Profile Picture
1.2.1. Size
1.2.1.1. 180 x 175px
1.3. Northsocial: Fangate
1.3.1. Size
1.3.1.1. 810 x 610px
1.3.2. Clear CTA: use arrows and like buttons
1.3.3. New node
1.3.4. New node
1.4. Northsocial: Header
1.4.1. Size
1.4.1.1. 810 x 210px
1.5. Custom Apps
1.5.1. Sizes
1.5.1.1. Max Width 810px
1.5.1.2. Above Fold Height 610px
1.5.1.3. App Logo
1.5.1.3.1. 75 x 75 px
1.5.1.4. App Icon
1.5.1.4.1. 16 x 16 px
1.5.1.5. About the App
1.5.1.5.1. 140 characters
1.5.1.6. Invite Friends Message
1.5.1.6.1. 232 characters
1.6. Tab photo
1.6.1. Design Specs: http://blog.tabsite.com/post/568/Facebook-Timeline-for-Pages-Image-Dimensions-Infographic
2. Google+
2.1. Cover photo
2.1.1. Design Specs: http://maheinfo.blogspot.com/2012/04/google-plus-profile-cover-size-photo.html
2.2. Profile photo
2.2.1. Design Specs: http://maheinfo.blogspot.com/2012/04/google-plus-profile-cover-size-photo.html
2.3. Thumbnail photo
2.3.1. Design Specs: http://maheinfo.blogspot.com/2012/04/google-plus-profile-cover-size-photo.html
3. Twitter
3.1. Profile Pic
3.1.1. 128 x 128px
3.1.2. 14 Tips for A Great Twitter Profile Picture: http://socialmediahive.com/twitter-profile-picture-size-all-you-need-to-know
3.2. Background
3.2.1. Design Specs: http://tweetstyle.com/design-specs/
3.2.2. 4 Ways to optimize your twitter background: http://www.blueglass.com/blog/4-ways-to-optimize-your-twitter-background/