You can learn more about art plagiarism here:
https://steemit.com/abuse/@jaguar.force/what-is-art-plagiarism-by-francis-leverett-golden inform yourself about the true scope and shades of art plagiarism.

**Plagiarism is Not only taking someones drawing/photograph/artwork and passing it as your own**, thats called art theft, and its only the most blatant form of art plagiarism, **the most common one is called art paraphrasing, which is what you are doing.**

In this case, the photograph is Copyrighted by the photographer, that means that the photographer reserves all the rights of the picture to herself, and that means that to make derivative works of that photograph, as for example Your Drawing, you need permission from the author to do so. Additionally since by posting it in Steemit you are monetizing it you also need permission from the author to do that as well.

Appropiation only applies for famous artworks as for example say the monalisa, where the original is easily and readily recognized because of its popularity, or in cases where the work is transformative, and not derivative as your drawing.