something similar to phpbb but for image galleries?

i've been googling around today for a nice image gallery hosting package and found a few but those few require registration fees which are sometimes hundreds of dollars. Anyone have suggestions for free packages? Idealy (sp?) the package can have people login and upload their images using a nice web interface, and the script will generate thumbnails and gallery html for said uploaded images.

i find phpbb's solution to forum hosting inspiring to say the least, hopefully a similar solution exists for hosting my own image galleries. of course i can code something up myself, but i'd rather not reinvent the wheel if there is a quality package already out there.

thanks.