buffer settings in php.ini?

Hello; I am having a strange breakdown in some dhtml that uses php to dynamically generated images and support data. The program is supposed to generate 9, 16, or 25 images. It does 9 without problems but breaks with 16, and 25. I've written the code to accommodate different numbers of images, not separate code for each size. From tracking the progress of the code (javascript/css/html and php) It appears to be some kind of a buffer limit problem. One array that the php is supposed to produce comes out fine when the function to produce it is isolated and run but breaks in the context of the code and appears to be the point where things go bad for the rest with 16 images. It is used to generate the tile images in the gd code. Each image is generated in a for loop. So, I'm wondering if generating 16 images is causing a buffer overflow, and if there is a gd specific buffer setting that can be increased, as well as the general limits for php in php.ini. Sorry, I don't remember where to look for all the php.ini info in the manual. I'm using php 5.1.2, gd 2.0.33 Thanks in advance. JK