[Plugin: NextGEN Gallery] Thumbnail Error

I have uploaded 182 photos into a gallery. When I went to generate a thumbnails page I received the following error on the page:

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 8208 bytes) in /home1/troopse3/public_html/wp-content/plugins/nextgen-gallery/lib/image.php on line 71

Any idea what’s causing this? I’m using the latest version of NextGen Gallery.