[Radiant] Image Caching

[Keith Bingman]

I am working on an image extension, which stores the images in the  
database, then resizes them on retrieval. To make this at all usable,  
I of course need to be able to cache the images. I had hoped to use  
the Radiant system to do this, but so far have been unable to make  
this work. I am basing the controller on the Radiant site_controller  
and have been able to write the image to the cache folder without  
problem.

The problems start when retrieving the image: first it does not  
recognize that an image has been cached and when I force it, then  
retrieving the image results in a blank page.

Two questions: should I even bother with the Radiant system? Does it  
bring me an advantage or should I just use the standard rails caching.

Second Question: what am I doing wrong? Can this system even cache  
images?

Here is the image_controller, anything totally stupid and obvious?  http://pastie.caboo.se/113246


Thanks for any help.

Keith Bingman