Explanation

F03 picks a picture [in this case of a badly wounded fighting cock, don’t know why] and sends it to F02 with the instruction to add a new picture that has a relation to it. How the two pictures are connected with each other is up to F02. There’s one demand: the picture must be taken from the internet. Next up is F01 who has to react to F02’s contribution, and so on.
The idea is that an interesting trip starts that leads through every corner of the internet.