Web-based image catalog software needed

I'm looking for a web-based image cataloging system for the following project:

I am in the process of scanning in 100 years of family photos. I want to be able to upload the full-res version so that other family members can access them. I was going to use Photopost, but it is lacking some key features:

• I need to be able to pre-define a list of tags that other users can choose from when uploading. These tags will be used to search the image database (i.e. fred jones, michigan, wedding). I estimate there will be 100-200 tags and each image may have many tags. Photopost allows each image to be added to up to three categories only.

• I need other users to be able to register to upload images, but each user registration must be approved by an admin. Photopost allows people to register and upload, but there is no approval process.

Also, the app must have a nice, clean interface like Photopost and automatically build thumbnails.

I'm willing to pay for an app that meets all the requirements.

Any advice?

Loren