Earlier quoted context omitted.
It seems to me that the human effort spent in creating the original images in an AI's data set is an important element to consider when thinking of the "difficulty" here.
Yes, that 4 GB of data can't be really independently generated, but the fact that a large chunk of that effort can be compressed into 4 GB is still amazing.
OTOH, if the 2 bytes is an index into a larger corpus of collected works, the question becomes more interesting.
OTOH, if the corpus is an ensemble of other 2-byte objects...