Also, if all the photos you've tried are being placed too low, you can
add a border to a photo.
Do you have any photo editing software program on your computer? Most people have Paint or Paint 3D bundled as part of Windows. There is also Paint.net which is a FREE software program for to download. (I have it.

) Essentially, you create a larger, blank background image than your current image in any color you want. Save that background image. Then you insert your photo on top as a "New Layer." Move it around to where you want. You can even shrink your photo to fit. Make sure it's well above the UPC code. Save it under a new name - NOT the name of your real image. You should now have your image inside a border. Then test it out on the Back Page.
Longer directions:
What you do is bring up the photo in your photo editing program. Click around till you find the image size. Note the size.
Then go to the Files button in the program. It will usually say something like Open (to look for a file on your device,) or Open NEW Image. Click on New Image. It will bring up a white background that is your new "photo." (You can also change the color to any color you want.) Make sure the DPI is 300 dpi or more.
Adjust the size of the photo so that it is LONGER than your current photo. Save it under a name like "Test background1". (Play around with it till you have a size you want that will fit the back page. You may already have another photo that takes up the whole back page. Use the dimensions of that photo.)
Then insert your current photo onto the background (as a new layer.) It should automatically be smaller/shorter. You can grab & adjust the corners to make it smaller and have a white border around it larger or smaller. Move it around, to where you want - leaving a space at the bottom near the UPC code. Save it again under a different name so it's a separate photo than the background & your photo. Then try it on the back page to see if you like it there.