Hmm - this doesn't seem to be working for me :-(. The code runs and does what it's supposed to do, but I never see a progress meter. Here's the structure of what I made:
tell application "Photos"
do some stuff, including set nPhotos
end tell
set progress total steps to nPhotos
set progress completed steps to 0
set progress description to "FILENAME TO DATE AND TITLE:"
repeat with i from 1 to nPhotos
set progress additional description to "Processing image " & i & " of " & nPhotos
tell application "Photos"
do some more stuff
end tell
set progress completed steps to i
end repeat
return
sorry about all the double-line spacing. For some reason all single carriage returns in by responses are ignored and what I add another I end up double line spacings. Quite annoying...