There are other properties that you set if you want the image to show up when the user performs specific action: hover, click, etc. You can find them in the Adding Images to Items section of our documentation.
You can then use the ItemDataBound event handler to bind the property to a data item field. Alternatively you can use the DataBindingscollection. Please, see the Using DataBindings article in our documentation for more info on the DataBindings collection and we also have a demo, which shows it in action:
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