Could you perhaps post an example which demonstrates ImageWidth and ImageHeight reporting different values on different machines? I haven't actually tested it but I find it hard to believe that those commands are variable in the way you describe; they just return the pixel dimensions of an image, and the number of pixels in a given image never change (assuming you never alter the image.)
Oh, and maybe do it in a new thread? This one is getting pretty lengthy and the example would be off-topic.
Oh, and maybe do it in a new thread? This one is getting pretty lengthy and the example would be off-topic.