This site performs automated image quality assessments and classifies each image into P5-P0. Beyond allowing as filter crtieria, the P5-P0 controls image retention. Current retention is as follows:
P5: 14 days P4: 14 days P3: 7 days P2: 3 days P1: 24 hours P0: 24 hoursThough varying wildly based on conditions, the above can translate into 300-400 images retained using 10-20MB JPG compressed and 50-75MB PNG uncompressed (original source images).