The screenshot format is used for storing app screenshots in the data/AUTHOR_ID/APP_ID/shots directory. The file names are 0001.ffs, 0002.ffs, etc. File content:
0x00: magic number (0x41).0x01to0x30: color palette. 16 colors in total, each color is stored as 3 bytes RGB.0x31to0x4b61: 160 rows, 120 bytes each. Every byte stores 2 pixels. One pixel is 4 bits representing the color offset in the color palette.
One screenshot is 19 Kb. 10k screenshots would take 184 Mb of storage.