Hello,
I would like to do a realtime compare with you... please send me a message on when you are available. I am Central time, and have some time options.
You mentioned that you are running OS X. You should be able to go into your System Volume, and find the Applications --> Utilities --> System Profiler application. That will scan your hardware, and peek inside the machine to see what your hardware really is.
I do not think you have a hardware problem -- you are seeing them good at first. I am wondering that when you save the image before uploading it, if you are introducing errors to it (perhaps saving as a .gif file and dithering the colors). I would like to download said image, and see if it distors here for me.
This will take some work.
Christian