He said me that the reference to his copyright is mandatory.
First: I think you may find some images without source reference if you search back my oldest posts. But just like in this case, I don't think the user who posts it claims it as their own work. Just to be sure, I nowadays always add a source link to images, but not all users do that. Especially in the Wall Observer thread I've seen many (innocent) cases.
Plagiarism isn't the same as a copyright violation. Plagiarism can get you banned, copyright violations can get you into other problems. Either way, plagiarism is handled by forum rules, and shouldn't be used for negative feedback:
The system is for handling trade risk, not for flagging people for good/bad posts/personalities/ideas.
The person himself admits that in his personal blog he publishes links for the author, but this is not necessary for the BT Forum. Bravo!
I posted the images and did not initially indicate the source as they were taken from my blog.
https://cont.ws/@inc/90101 (Where I indicated the name of the photographer without ambiguity).
I specifically quoted the author of these photos, he is against his property being disposed of without mentioning it.
In my trust, I indicated that I personally do not want to trust the plagiarist, this is my personal trust. Moreover, I will not have any trade deals with him. You can do something else.