Hi Steemians! If someone is claiming to have created original art... drawings, paintings and photographs and your gut says something's amiss, simply use the free reverse image search at http://www.tineye.com.
Go to the image in question, and upload or right click to copy and paste the photo address into the search bar. And, instantly, you'll see results.
FOR EXAMPLE...
My Original Art - Alpaca in Field with Fence... Sorry, not for sale :)
No Findings or Limited Findings with Original Poster's URL
I encourage you to test it out on other images. It's amazing how technology works! Sometimes you'll see that an image has been used 10 times or 150 times because it's in the public domain.
EXAMPLE...
Help Steemit Photo Sheriff 
https://steemit.com/photography/@brendanwenzel/photo-thieves-beware-you-re-looking-at-the-new-photo-sheriff-on-steemit
Please Resteem to stamp out posers.... and as always, happy Steemin'!