[mcg1969]

This is false. Using the "width" and "height" commands does NOT reduce the size of the image downloaded. The same image is downloaded regardless---and then it is shrunk in your computer to the size specified.

[An.American.Expatriate]

Okay, I stand corrected. I do recall though that the Mod recomended this for performance. I don't know if that is true though. I have broadband so I can hardly tell the difference.

[Engraved-on-His-hands]

I'm not an expert on this, but I think that the problem isn't just the image size but the necessary calculation of the image size by the browser.

...one of the biggest delays is that most browsers won't display the entire page until they've calculated the height and width of all the images. (from The Complete Idiot's Guide to Creating a Web Page)

Therefore, having the height and width attributes specified should speed up the process.