- format version - 1 byte (counting up start at 0)
- image width in pixels - 2 bytes
- image height in pixels - 2 bytes
- comment length in bytes - 1 byte
- comment - ascii encoding, length variable (see comment length in bytes)
- information per pixel - 3 bytes (RGB value, no alpha channel)
- image data compression (gzip?)
- alpha channel (mayhaps?)