For this tutorial I'll be using Photoshop to put an image inside text. It requires a clipping mask, which is easy to make once you know how. Photoshop CS4 was used for these screen shots, but you should be able to follow along with other versions.
To begin, right click on the below link to save a practice file to your computer, then open the image in Photoshop.
Practice File: STgolf-practicefile.png
Photo © Bruce King, used with permission.