[Plugin: NextGEN Gallery] Picture uploads fails to create thumbnail

Hi.
If i try to upload an image to my gallery, it uploads the image itself, but allways throws an error, that it could not make the thumbnail.
Error message:

img_0009.jpg (Error : Exceed Memory limit. Require : 32.47 MByte)

The image itsels is around 800kb.
What is the problem?
There is no difference, if i try to upload a single image, or around 15.
Please help here