How many pictures can I upload – NextGen Gallery

How many pictures (and it’s image size) can i upload using NextGEN Gallery. I can’t upload. I’m getting the following error message:

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 4800 bytes) in /misc/20/000/134/555/3/user/web/redappleplayschool.com/usbrands/wp-content/plugins/nextgen-gallery/lib/gd.thumbnail.inc.php on line 723

What shall i do? I need this for my products gallery. Thanks and God bless!