It would help if you could explain the steps you're following, and also what you mean by "the pixels are really messed up".
Sorry, I guess that was a little vague. When I crop a photo it of course makes the photo smaller. When I print that picture it is very fuzzy as it changed the pixels after cropping.
But how are you cropping? The crop tool often resamples your image, so we need to know exactly what you have been doing, step by step.
Sorry, but I need to ask - when you say the photo becomes 'smaller', and the 'pixels are really messed up', is it possible that you're scaling the picture instead of cropping it?
Do you want to print just a certain part of the image and do away with the rest (cropping), or keep the entire picture, but just print a smaller copy by reducing its size (resizing or scaling)?