transformations on images - simple question

This is hopefully a simple question, how do I perform a transformation on a pixel array in openGL? Ie, I want to warp an image (rotate it in space and view it or view it from an angle) once I have drawn it with glDrawPixels(). I can draw the pixel array (image) and rotate my models that are displayed with the image, but the transformation is not applied to the image.

Pixel data and geometric data travel down different portions of the pipeline; you cannot apply geometric transformations to the former.

If you were to convert the glDrawPixels() calls to geometry drawn with textures, then what you want would not be very challenging, but the way you are doing it now will present many problems if you want to transform.