Methods and apparatus, including computer program products, implementing and using techniques for analyzing images of cells and extraction of biologically significant features from the cell images, such as from granules representing intercellular organelles or other features in the images. In various embodiments, the extracted features can include the number of granules, the total surface area of the granules, the mean or maximum intensities of the granules, etc. These features can be determined on a cell-by cell basis, or for particular regions within a single cell, or for various groups of cells.