I've got a project where we want to be processing large jpegs (5-6MB) with apache and php (using GD library).

My understanding is that the server converts the image into a BMP making it quite ram heavy and currently we're unable to do it with our 1gb of memory.

Here's the error we get:

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 17408 bytes)

How much ram should we be looking at running with to process images of this size?

Edit:

As Chris S the purist highlighted below, my post is apparently vague.

I am doing the most basic and common manipulation of an image, say turning it from a 4352px x 3264px jpg of 5mb in size, to a 900px x 675px file.