How to insert an image inside another image in Open GL ES programming?

Question

Hi,

i am learning to program in Open GL ES 1.1 for iphone to make 2D game.

In my game I need to put panels in the screen and inside the panels i will put the elements. But to be able to do this, I need to know how to put an image inside another in Open GL ES 1.1. I just know how to put directly in the screen according this tutorial

http://videos.71squared.com/6396596

Any Idea??

Thanks.