If the cover on a Facebook page looks blurry, it is likely because the Social Cover has been uploaded to a Personal Facebook profile page instead of a Business Facebook Page.
When uploading a Social Covers image to a social media page, you may notice that the image quality is reduced for the Facebook covers and not for covers uploaded to other sites (like Google or LinkedIn).
First, consider which Facebook page the cover is being uploaded to. Social Covers does not support automation or the creation of Facebook PROFILE page cover images. Instead, Social Covers only supports images and automation for BUSINESS pages.
NOTE: Learn How is a Personal Profile different from a Business Page
While the Facebook Profile is geared toward personal communication with "friends", the Business Page is geared towards promoting your business and viewers can Like, Follow, Share, and send you a message. It is also the page where you can see the review and overall reputation of a business.
Next, check the image size you are attempting to use. If it is over 100KB, consider reducing the file size.
NOTE: How to resize an image using Microsoft Office
Otherwise, Facebook will compress the profile cover image quality to under 100KB resulting in a distorted image on both mobile and desktop.
While BUSINESS pages also have their image quality compressed, it’s not nearly as low as the PROFILE page.