Hmm. Are you defining the images in the DXPlayer Configuration dialog? When you select something like a fader or slider that takes images, the Images button becomes active, and you can define them there. Background should be long and skinny, slider shortish and squat, but use images that share a same dimension along the short axis for best result. Also, try BMPs, as I think that's what DXPlayer prefers. I got PNGs to work, but no transparency.
anyway, not exactly sure that's what you were asking.