Lepidoptera and some other life forms: http://www.funet.fi/pub/sci/bio/life/intro.html
One of the original image gallery web-sites. Based in Finland.
The Lepidoptera section is the most useful with species-level links to photographs on other sites.
For macro-lepidoptera, the site includes the author's own photographs (many of set specimens), lists foodplants and shows world distribution maps.