Adding a Caption to a Digital Photo

My Mom doesn't have or want a computer. I have been uploading photos to WalMart.com and then having them mailed to her. I'm trying to find out if there is a way to add a caption to the individual photo prior to uploading it to the WalMart website. Already asked WalMart about doing it once it has been uploaded - not possible unless I am creating a book or calendar of the photos.

It is difficult to tell Mom about a photo because I can't figure out which photo Mom is looking at.

Thanks for your help.