If your images look stretched, squished, or distorted in Album Proofer, this is most likely because you need to add a cover.
Click Add Cover. If you designed a cover for this album, you can see instructions on adding your cover here.
If you don't need to add your own cover, just choose a black or brown swatch and then click Add Cover. Your album will automatically update to reflect the change and your images will no longer look distorted.