Yeah, this is all wrong. You can't just upload uncropped, unresized, unsharpened files, and expect them to print properly.
As I said earlier, your 8x10 print jpegs should be (usually) between 500KB and 2MB.
http://www.damiensymonds.net/2011/09/cropping-tutorial.html
http://www.damiensymonds.net/trainingsharp.html