Cover photos: 851px by 315px:
- To avoid compression when you upload your cover photo, make sure the file size is less than 100KB
- Save your image as a JPEG with an sRGB color profile
- Photos can be up to 5MB; animated GIFs can be up to 3MB.
- Twitter accepts GIF, JPEG and PNG files.
- Twitter DOES NOT accept BMP or TIFF files.
- Pictures will be automatically scaled for display in the expanded Tweet and in the user gallery.