Thanks for writing.
Pan and zoom image uses scale transform internally. The scale transform redraws the zoomed element only after a certain threshold. This is a performance optimization inside the Silverlight framework which avoids redrawing the whole image every time a manipulation occurs. When the framework decides that it has reached a certain zoom level it redraws the element once.
Which WP8 image manipulation scale effects are you referring to so that I can compare them?
the Telerik team
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