Just fyi
Hudson Gray asked:
If the picture is of an item in a museum, one they sell slides or postcards of after asking a photographer to take the images for them, and you drew something off that....I don't know where that stands.
From what I know of a straight 'poster' of a fine art image:
The teacher of my Renaissance Studies in his "Making of the Western Mind" series had a print from Raphael and it was the often-discussed "School of Athens". The museum that houses the art owns all reproduction rights and because it was recognizeable, to even do a poster to sell for the nonprofit/school he was setting up required a fee and proper recognition.
From what I heard of web/other artists:
If you make the image up to 80 percent your own with major changes in color, style, adding or subtracting elements, it is likely to be recognized as yours.
Now this is me:
I would obsessively redo studies even if they originally came from three different sources even if 60 percent was from older work of mine (say a portrait from a fine art image; a posed photograph from an out of print photographer; my own sketches) until I or someone says, "hey, that looks like your style."
My Queen of Swords for the last Aeclectic.net deck was one of those decade long projects, even though the majority of photos were of my own family and my own sketches. I've included in different style collage or study ideas and redrew it as well or added details...
If you have your own backgrounds, calligraphy or characteristic line-work to add, this also makes the image more your own. I winced once when I recognized a Western artist selling a not-her-own combination from a commercial rubber stamp with recognizeable rubber stamp calligraphy and translation. It is considered illegal now, unless you use rubber stamps from people who guarentee copyright free or allow you to use their 'angel' image..Her collage of papers was fine, but she used it as a backdrop for the stamp that was easily obtained at a drugstore, local artstore or fine stationery store. Many Asians who frequent the same stores would pay five to seven dollars for the stamp and paper scraps they could pick up for two or three dollars..., not seventy-five dollars for what the artist wanted.
I don't know if this information helps.
BTW, I had seen watercolor and line drawings done by this published artist decades before, so I felt like what I saw in the store was not a good thing.
Best wishes,
Cerulean