KD0OFN (Stillwater, MN): SSTV Image Capture on 14.230Mhz
Equipment: DX-EE Multi-Dipole @ 25', Icom IC-7410, MMSSTV.lib (Win7)

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 hours
Though 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).