which Category should I use?

Hi everyone, 

I tired to upload a image of stone isolated on transparent background. I checked other images in Adobe stock what kind of category they used because I don't know what should I use and the Category of these images are stone and rock! I could't find such Category from the Category list. Can you please help me to figure out where to put in such Category? If I can't use Category stone and rock, what kind of Category should I use for my image?

And there is another question. Adobe rejected all my photos of wood or stone texture background (I attached one), can you please help to have a look where is the problem of my image? 

Thank you very much, and have a great day!

Naige