
For the moment, Flickr seems like the most useful option, as a lot of people already have accounts, and it would be relatively easy to organize the photos by color. In addition, people can view basic Flickr photo collections without having to have a Yahoo or Flickr membership.
I currently have more than 10,000 photographs of sea glass, most of them close-ups of individual pieces, in almost every color imaginable. These include a lot unusual rarities and unique pieces, including my collection of sea glass marbles.
Of course, this will very much be a "labor of love" and will probably take months-- if not years-- to complete. I just doing what often helps me get a project rolling: making a public commitment to the idea.