To display images, you'll need something that displays each item with an image individually. How this is set up will depend on your project. You'll also need a column listing the url where your image lives on the web
On your dashboard, you'll need to include a Web Page Object where you want your image to display. Drag it where you want and give it the url <Image>, where <Image> is the name of the column with urls in it.
Then go into Dashboard > Actions to make the magic work.
In Add or Edit Action, select the sheet you want to use as a selector (the list of individual items), and in url list the column name in sharp brackets (<Image> here). In URL Target, make sure to select Web Page Object if you want the image to display on your dashboard.