Herpesvirus Web - - Large collection of microscopic images of herpesvirus infected cells, including electron microscopy and fluorescence microscopy.
Image Library from Russell Kightley Media - - Scientific Medical Biological stock images. Microbes, viruses, animal and plant cells. Digital illustrations available for license.
Imaging Technology Group Gallery - - Images and brief descriptions of cellular structures and stages of mitosis produced by ITG users and staff - from Univ. of Illinois at Urbana-Champaign.
Molecular Probes Gallery - - Very pretty image gallery demonstrating results using fluorescent probes - from Molecular Probes, Inc.