I'm thinking that you aren't saving them correctly. Make sure that you click on the first image to open it up. Then you have to click on the "download" button to get the largest size. Do not right click to "copy" you will need to download it and save it to your pictures.
For the regular pages, I saved them at 300 resolution and 8.5x11 inches so they should not be blurry when you print unless you saved the thumbnail image. If you are still having problems send me a pm.
If you are trying to incresae the size of the 4x6 pages, they will be blurry as they were meant to print at 4x6 inches and will be blurry if you try to make them any bigger.