If images appear as empty grey boxes when viewed in Show Images view then read the following...

You may encounter this problem if you rename the album file from outside of ProSelect while the Album is still open in ProSelect.  This is because ProSelect cannot correctly update the Album when you close it. Obviously the way to avoid this is not to do it! Either only rename your album files after you close them in ProSelect or use ProSelect's Save As... to create a copy with a different name.

Once this problem has occurred, the album is no longer usable until you repair it using the procedures below.

Any missing images from albums will display a yellow caution symbol in the bottom left corner of the image's thumbnail so you can identify those images.

HOW TO REPAIR AN ALBUM

To fix an album with missing images:

1. Use Find Original Images (Album Menu -> Originals Images) to make sure all the original images are accessible. These will be needed to reload the images.
2. Rebuild the Album using Compact Album (under File Menu). This leaves the new album open in ProSelect and saves the original album in a different file with the words "(old)" added to the end of the file name.
3. In ProSelect 2010r1 or older, run Verify Album (under File Menu) to locate any missing images in the new album.
4. Select all the thumbnails that are marked as missing. These are marked with a caution symbol in the bottom left corner. Note: you can't reload images created using Custom Actions, so don't include these in the selection.
5. Use Reload Selected Images (Album Menu -> Originals Images) to reload the missing images.
6. Save the Album.

Note: If you have images in different tabs or sets, for steps 4 & 5, you will need to select the thumbnails and re-load them separately. You can use Show All Sets Together (under the View Menu) to allow you to see and select images in all sets in the same tab at once and/or move all images into the same tab and select them together.

If you have any missing images that are the result of running Custom Actions, these should be deleted, then run the actions on the images again.

In ProSelect 2010r1 and older 
In ProSelect 2010r1 or older, this symbol only appears after you have either tried to view a missing image, or you have run Verify Album (under the File Menu) which checks all images (ProSelect 2011r1 and newer does this automatically).