>What is the unit of measurement for the width and height of an image control?
I think that would be pixels - one pixel is one point on the screen.
To convert that to cm. is doubtul, since the same dot will look larger on a larger screen.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)