I did some experiments, and it seems to kick out at higher sizes. One image worked up to about 2300 pixels high, and at 2500 went white and didn't render. I'm going to try deleting certain objects and see if it's a specific model that's causing problems. I changed the virtual memory size and it does it less now, but a full page scene for me (3150 x 2025 pixels) still hits a wall sometimes. Thanks for the suggestions!