Where is the line between plagiarism and influence of another artist

[Pavel]

Сообщение от художник Федотов

of Course this is more so, but I assume other exotic cases for potential justification of plagiarism...for Example, "plagiate", accidentally saw on the Internet, freely available, beautiful picture, small format(in pixels), thought it is a beautiful photo, signature small and barely visible, and took my picture...

Or: to him who brought the picture of the original, where it was not visible signature and asked me to make her a picture...Then not take her...the Artist, who is suspected of plagiarism, say, @1,@I blame, he came to me... [/B]

I don't like painting with photo. It kind of dull ,though the profane creates the impression of complexity, delanote and buy.
Plagiarism is a repetition of the work for commercial purposes-this is theft.
And creativity is the notion of influence, but it is for creativity.