Some ideas for normal F11 msg:
1) "Not an image file. Unable to do Full Screen Preview"
2) "Must be an image file to preview in Full Screen mode"
3) "Full Screen Preview is only for image files"
For excluded, I don't think you need to point out where to set it...so..
1) "This image file type has been excluded from preview"
2) "Unable to preview. File type is excluded"
3) "Must use defined external application for this file type"
These are what I can up with in a few minutes...maybe not the best, but some alternatives, anyway...
However, I still hope you may consider the backup method of using IP preview...
admin wrote:As you see I went all the way, and I love it! Should have done that on day one.
You're not the only one who feels that way!!

I'm
very pleased with the results! Makes my usage MUCH easier and quicker!
Now if I don't have IP open, I can just F11 on a pix and then browse thru a few others, do F11 and I'm back to full list...YEAAAAA!!!! GREAT!!
I'm also happy that I mentioned this issue, as it was one of little things that made usage just a bit round-a-bout...