Imageshack is difficult to master IMO, that's why I use photobucket.com for all of my pictures. It's easy to get them uploaded in the correct size on there and you can just paste the code onto ACNA and it will display correctly. Check around in the "how-to's" sticky at the top of this section, I have a photobucket how-to in there.
***edit*** Here is the how-to's thread, look here for the photobucket how-to.
'98 Aurora w/ Accurate Engines port & polished VIN Y 4.6 bored.30 over, NSP stage 3 PCM, K&N intake, performance exhaust, Razzi skirts, Lund wing, strut bar, custom paint, went on a diet and lost 160 lb.