Where can I find the actual images that were shown on the screen during The Glass Menagerie?
It is quite unlikely that you will find any of the actual images or "screen legends" used in a production of The Glass Menagerie as even the original 1945 Broadway production of the play did not include them.
Tennessee Williams' original idea was:
"The legend or image upon the screen will strengthen the effect of what is merely allusion in the writing and allow the primary point to be made more simply and lightly than if the entire responsibility were on the spoken word."
Here are some of the screen legends:
“Ou sont les neiges d’antan”
"Amanda as a girl on a porch, greeting callers"
“You think I’m in love with Continental Shoemakers?”
"A swarm of typewriters"
"Sailing vessel with Jolly Roger"
"I don't suppose you remember me at all!"
Most directors of the play have deemed the inclusion of these images with subtitles superflous. Williams did not object to their absense during the 1945 production, and very few subsequent productions made use of them.
So, if you want to be absolutely true to the letter of Williams' original conception of the play, I suppose you could Photoshop your own images. But if you want to follow actual theater performance tradition on the subject of the "screen legends," you will eschew them.