The ideal image size for your Facebook cover photo is 851px by 315px. For best results, make sure your image is JPG format, with RGB color, and less than 100 KB. Facebook will automatically format your photo to fit the cover photo slot, so if it’s not sized correctly, you might experience some distortion.
Why does Facebook cover photo look blurry?
Facebook cover photos are 820 pixels wide and 312 pixels tall for desktop, and 640 pixels wide by 360 pixels tall for mobile. If your uploaded image is smaller than these dimensions, Facebook will stretch it to fit, making it look blurry. A cover photo can take your Facebook Business Page to the next level.
According to Facebook, cover photos display at 820 pixels wide by 312 pixels tall on desktop computers and 640 pixels wide by 360 pixels tall on smartphones. For your cover photo to look great on both desktop and mobile, we recommend using the dimensions 820px wide by 360px tall.