Justine, I'm back at my computer and will share a method for making 12 x 12" papers fit onto 8.5 x 11" canvases without losing the edges. This doesn't work for all papers, but most. Jen White, at Digital Scrapper, recently shared this with us.
Open your 12 x 12 paper in PS or PSE. It will be considered your SOURCE document.
Open a new canvas the size you plan to scrap (such as 8.5 x 11). This will be considered your TARGET document.
Activate the Source document, then click CMD (CTRL on Windows?) + OPT + I
That will open a dialogue box*. Let it just sit there while you ...
...go up to your menu bar and select Window then at the bottom, select the Target Document where you want the paper to go (since I do this first thing, before saving it is usually something like "Untitled-1").
Now (notice that the width and height has changed) click OK on the *dialogue box.
Drag the now smaller paper over to the canvas you want to work on.
CLOSE THE PAPER window WITHOUT SAVING IT. That makes it go back to your file in the original (12 x 12") size.
Hope this works for you.