Converting Cell Size to Pixel Dimensions

Hi! I am attempting to cut a 1024x1024 pixel image at the native resolution of the image. In order to do that, I need to know the dimensions of the Clipping Graphic (GraphicSize).

If the projection is in UTM space, the cell size is already in pixels/meters, so the math is fairly easy.

Formula:
GraphicSize = (CellSize * PixelDimensions)

Example:
512 = (0.5 * 1024)

How will I do that for Decimal Degrees, assuming I cannot convert the layer into UTM space?

Thanks!