Social media messages have text and images, and those images should sink with the text. So, it becomes essential for you to draw images and keep to size in accordance to the set rules and guidelines of social media networking sites. Online you can find several networking sites, such as, FaceBook, Twitter, Linkdln, Pinterest, Instagram, and YouTube. Each social media image is bound to follow certain dimension otherwise those would get distorted or does not form accordingly.
Images are measured in pixels and graphic designer will have to keep in mind these dimensions thoroughly for better imaging. In Facebook, you will have to design for cover photo (851x 315), Profile photo (180x180), link image (1200x627), and shared image (1200x900). When a twitter image comes up to post, graphics must contain cover photo (1500x500), profile photo (400x400), and shared image (506X506). In the case of Google plus, cover photo should be cropped to (1080x6508), profile photo (250x250), and shared image (497x373).
Graphic Designers Need to Maintain Right Profile Background
In the case of Linkedin, designers will have to maintain profile background between 1000x425 and 4000x4000, profile photo 400x400, company logo 100x60, company banner image 646x220, and career cover photo 974 x300. For pinterest, the profile photo must be 165x165, Pins in the feed 236x scaled height, and the clicked pins 600 to 735 x scaled height, and board thumbnail 222x150. Similarly, the profile photo for the YouTube is 800x800, channel cover photo 2560x1440, and custom video thumbnail 1280 x 760. With information consolidated about social media at one place, aspiring graphics can use it as reference.

Source: constantcontact