"That's not what you're paid for." I believe he clearly stated that it was done during "free time" which I believe he means during breaks etc. and not during time he is supposed to be doing other work. Since he was given permission to use the internet during those times the company has no right dismissing him without giving a warning that certain sites are off limits on the work computer. As rosity is not a "porn site", but an art site, they should have given a warning that rosity is considered by them to also be off limits. A clear case of unfair dismissal.