Optimization.

A question about optimization. First of all this is a topic of great interest to me and a topic I'm continuously researching around. I was wondering if it was possible to post a blog giving what you feel the 'optimal' dimensions and file size on:

• Images
• Page Sizes

As I said it is a topic I am researching around so I am only looking for the numbers that come 'off the top of your head,' so I can structure my layouts inside of those constraints (thx.)