Currently, the RadButton uses the image for the background of the button, behind the text. It can't be aligned next to the text. .
If you'd like to see the dev team add this to RadButton, you can submit a Feature Request in the UI for Xamarin Feedback Portal
Lance | Tech Support Engineer, Sr.
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Feedback Portal
and vote to affect the priority of the items