Image analysis is applied to study the precipitation of calcium oxalate in a semi-batch single- and double-feed reactor. The feed consists in un-premixed potassium oxalate and calcium chloride solutions. The effect of various operating conditions and feeding strategies on the yield of calcium oxalate mono-, di-, and tri-hydrates, the degree of agglomeration, and the crystal size is studied by image analysis. Statistical validity of the image analysis for crystal shape characterization and experimental precision is carefully investigated. Agglomeration and face growth kinetics are quantified.