A cover is the larger photo at the top of your timeline, right above your profile picture. Cover images are public, which means anyone visiting your timeline will be able to see them.
The default facebook cover photo size of facebook is 350 x 315 , that means facebook will scale all your photos and images to this size when you add any picture in facebook cover section.
To add a cover image to your timeline:
- Go to your timeline
- Click Add a Cover
- Choose whether you want to upload a new photo or pick a photo from one of your existing photo albums
- Once you choose a photo, you can reposition it by clicking on the image and dragging it up or down
- Click Save
Please not you may get an error if you try to upload a photo that is not big enough.so try to upload photo of high resolution