picture control problem

[sincebaugh]

I am using a picture control to simulate a hover button. I am displaying
an original image, then a highlighted image when the mouse is over the control,
then a third image when the mouse is pressed. It has worked on dozens of
different machines, but now I found out that on one machine the original
image is just a blurred random image, but the highlighted and pressed images
display ok. any suggestions on what might cause this?