Our lab recently published a paper on the open-source program we built for analyzing epifluorescence microscopy images of microorganisms. The Microbial Image Analysis (MiA) program aims to provide flexibility for the selection, identification, and quantification of cells that vary in size and fluorescence intensity (natural or probe-conferred) within natural microbial communities or cultures. The development of the graphical user interfaces (GUIs) was built in collaboration with an interdisciplinary team of undergraduate students in Biology, Physics and Computer Science. This work was primarily supported by the Cal Poly Research, Scholarly, and Creative Activities Grant Program and the Bill and Linda Frost Fund.