There are a number of things that can contribute to resolution problems. One could be that the particular page did not load fully. Another problem may be your image settings. If other pictures look pixelated, and if you have an internet accelerator on, it may be set to lower image quality for the sake of speed.
However, if you are talking about size problems, and not quality, then you may need to up you monitor resolution to accomodate the image. Also try resizing the window, which usually solves the problem.
If none of these responses have answered your question, you may need to elaborate. What is your exact issue? We cannot help you if you do not tell us what is wrong exactly.