Well the cheap easy way to get that text to pop up would be use a comment for the photo.
Example from www.google.com:
<img src=/logos/olympics08_martialarts.gif width=285 height=110 border=0 alt="Beijing 2008" title="Beijing 2008">
The key tags here are alt and title.
ALT= is text that is displayed on the X out image if the photo doesn't load.
TITLE= is the text that is displayed when the mouse is held over the image.