The RadRotator is designed to use a sprite image for defining the appearance of the control buttons. If you want to change the buttons by customizing the skin of the rotator, you need to follow the steps in this help article
and create a new sprite from an existing one by keeping its original size. Any change of the sprite's size would require modifications in the rotator's skin to adjust the background position.
Another possible approach is to use the ControlButtons inner property
of the control to customize the buttons, which I already suggested in my previous post.
All the best,
the Telerik team
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