Pixel Memory Size Setting??

Hi,

I am noticing that there are a lot of files being written in tmp.  From 
what I gather, this happens when the image can no longer fit in the 
alloted memory space.  Is that correct?  Under what other conditions 
does this happen?  Also! How do I programmatically  set the memory to 
use, so that it doesn't write out any more tmp files?

-- 
Gavin M. Bell
--

 "I'm trying real hard to be the shepherd."
               -Samuel Jackson (Pulp Fiction)