If you are sharing images on social media networks, you’ll want your images to appear as you intended, and not cropped to fit a space-mandated format. Use these dimensions when you design and upload your images to individual social media networks:
Facebook 1200X628
Twitter 1024X512
LinkedIn 800X600
Google 800X1200
Pinterest 735X1102
Instagram 1080X1080
For more detailed information about sharing images on Social Media networks, check these sites:
https://blog.bufferapp.com/ideal-image-sizes-social-media-posts (the data source for this article)
http://visual.ly/essential-social-media-image-dimensions-cheat-sheet-2015