Adding TEXT over an Image

Good Evening: I would like to know if it is possible to add text over an image. If so can someone please help me with it? Here is what I would like to do. I currently have a "random masthead" that I pull from my database (the location of the image is stored there with other info such as credits and description) I would like to overlay on top of the Masthead the words "Administration Mode" without me having to create a duplicate copy of the original mastheads and save them again... I would like to be able to just have a bit of code that would add on top. I ask this because I have too many masthead options right now that it would be infeasable for me to create duplicates of each one to just add Administration Mode as an overlay. Thank You. Gary I am new to PHP and currently am runing PHP 4