Method Image.AVS._decode()
- Method _decode
 decode(objectstringdata)
_decode(mappingstringdata)
encode(stringobjectimage,objectobject|voidalpha)- Description
 - 
Handle encoding and decoding of AVS-X images. AVS is rather trivial, and not really useful, but:
An AVS file is a raw (uncompressed) 24 bit image file with alpha. The alpha channel is 8 bit, and there is no separate alpha for r, g and b.