Resize plane (or primitive) based on size of texture?

Unity Engine
1

I am currently trying to do the decompress texture method Eric5h5 mentioned here http://forum.unity3d.com/viewtopic.php?t=19417&highlight=readpixels

As suggested,I have am displaying the texture for one frame so the camera only renders it, but was wondering how best to resize the plane for non-square textures like 512*256.

2

Instead of dealing with resizing objects it is probably better to just used the GL drawing methods to draw the texture onscreen and then read the pixels from that.