You want to display a textured quad so that the texture appears with the same number of pixels on screen as it has in the image?
One way to do this is:
Set texture coordinates to bottome left (0, 0), bottom right (1,0), top right (1, 1), and top left (0, 1).
Set the projection matrix to window size with gluOrtho2D, set modelview matrix to identity, and draw your quad in the size of the original texture image.
[This message has been edited by Relic (edited 03-06-2001).]