Ive heard somewhere that if u make images, and have the stretch across, other people might see ur site scrunched up or really spread out....is there any way to aviod this or check it? and also, with the <hr> tag for a line...do u have to set ur own length (how far it goes across) b/c then again, if u set it to where its fine on ur moniter, then people with smaller moniters might have the scrollbar on the bottom of the page....?

The only way to really check is to keep changeing your own screen resolution and looking at it...but if your too lazy to do that try browser sizer (http://www.applythis.com/browsersizer/)
Theres no 'code' or anything that will make it work in all resolutions, you just need to keep checking as you go along and then find solutions to things as and when they come up.

i didnt know u could change the resolution of ur screen...i guess i'll try that...

lets get this straight, your image will only strech if you use % in your height and width attributes. For example i build my site to work in 800X600 res, however nothing will strech when the res is made higher because i used actual numbers instead of percents. And yes i did that on purpose.