Photoshop CS4 from Adobe Systems is a powerful image and photo editor but not a tool for scientific image analysis.
The software has a huge multitude of tools for image processing (and, of course, photo manipulation). There is no point in listing them here. The “extended” version also has a few fun features like auto-blending or content-aware scaling.
However, its image analysis capabilities are very limited. After searching for a while, just these two below all I found:
Use selection tools to define and calculate distance, perimeter, area, and many other measurements. Record data points in a Measurement Log and then export the data, including histogram data, to a spreadsheet for further quantitative analysis.
Easily and accurately tally objects or features in scientific images with the Count tool, which eliminates the need to perform manual calculations or rely on visual assessments of changes from image to image. Save even more time by performing multiple counts in a single image. Use separate colors for each count and save your counts in the file.
Adobe Photoshop CS4 Extended is priced at $999.
See also other Image analysis software.