Imgembed is a “crowdsourced” collection of what’s now up to one million images that are free to use as long as you credit the photographer (it automatically appears with the embed code). You can also pay if you don’t want to have a header with an attribution. And you can contribute your own photos, too.
You can read more about it here at 10,000 Words, and I’ve embedded a short video about it below. I’m adding it to The Best Online Sources For Images.
Snapshot plugins! I don’t see the use of this, it sounds like a glorified stock image portal with the only exception of tracking your created images. I’d be more inclined to consider this if the imagembed web site said anything about who’s behind it and what their revenue model is.