Quote - Books by David , so perfect resize works, ? I had a go with one recently , free trial, and it just came out pixelated as it would have without the software, I better check out which one is used .... Someone had given me a 5 mb image they wanted used as a poster...... 

Well, it's worked for me so far. I've had images as large as 3 ft. by 5 ft printed and they came out beautifully. I've tried .jpgs at about 600x750 and the larger they get the worse they look, but the quality wasn't great to start with, so I think it all comes down to the quality of the original image.

After a quick read of the article xerxes references above, I think it says the same thing.

There are also several adustable settings in Perfect Resize that can effect the quality of the final image (for good or bad).