I walked past an art gallery in my town today and saw an exact copy of one of my images in a painting format? Is this legal? I read through the licencing on the stock sites and don't see anywhere where this is permitted? Any advice would be appreciated!

OK.. so i need some advice or if you can steer me to an old thread that covers this i would be most greatfull... i did a reverse google search for one of my images and found an art gallery in Australia (i live in Africa) selling two of my images. I know this is illegal but i don't know what the best way is to deal with this? Any advice would be much appreciated. I am going to send them a 'ghost' email asking for the prices of the images and how i can go about buying it just to understand their business better... There are no prices published on their website... to say i am pissed off would be an understatement ...