I am looking for a freely distributed dataset of microscopic images. I am hoping to find a dataset that would feature histological images before and after staining (e.g. H&E or some other standard one, preferably). I have been searching through various databases, but I cannot find a proper set. I hope the sample size to be at least about 100. Suggestions?
Virtual fly brain (http://www.virtualflybrain.org/site/stacks/index.htm) is an excellent database of fly (Drosophila) brain sections, which can be electronically processed/annotated/highlighted on the fly to show different areas of the fly brain as an overlay on top of the original images.
Alternatively, you can use BrainTrap (http://fruitfly.inf.ed.ac.uk/braintrap/) for the expression of proteins in the fly (Drosophila) brain using brain sections. Another database which has silver stains of Drosophila brain sections is the flybrain (http://flybrain.neurobio.arizona.edu/Flybrain/html/atlas/) database. This database also contains 3D models of different fly brain structures and much more!
I'm sure there are many many similar databases, but these are the ones I knew of, which are widely used in the Drosophila community.