Adding an image to your RSS feed can make it look more professional. As defined in the RSS specification, feed images are relatively small. The maximum allowed width is 144 pixels and the maximum height is 400 pixels. Typically icons, logos, or other small images are used for RSS feed images.
RSS feed images are not included inside an RSS feed's file. An RSS feed's image is a separate image file that is pointed to by your feed. An RSS feed reader will download your feed, and then download the image your feed points to. If you use FeedForAll to load an image from disk, or to modify an existing feed's image, you will need to upload it along with your feed to your Web site.
Only .gif, .jpg, and .png image file formats are allowed by the RSS specification.
Link vs URL:
One common question is 'What is the difference between the Link field and the URL field on the Images tab?' The Link field is the Web address of a Web page that has information that relates to this feed. It is the location the user is taken to when clicking on the link. In most cases the Link field should be the same as the Link field on the Feeds tab.
The URL field is the Web address of the image file itself.