So I had a bit of an idea... 
Backstory: I'm HORRIBLE at coming up with what to put in a layout. Absolutely terrible! 
Idea: This forum post could include things you want to see as graphics or ideas that are more specific than 'horse in a forest', and possibly something you want to see for your horses (fun for themes, etc)
Graphic makers could tackle these and then either stick them in the auctions or sell directly to the one who came up with the idea. 

I like this idea since it'll give more specific info (not to the letter or anything) but just provide some creative and fun ways to do things with pics. 
I figure then graphics might be a more motivating sell/buy aspect. Anything to increase game productivity! 

Thanks all. 
Hoping for feedback. 

For layouts, it doesn't have to just be animals! I like just random cool swirly designs. :)

I think I like my layouts similar to my model horses - in unusual positions 

Horses rolling, rearing, bucking, pawing etc. rather than standing/cantering

Spiritesque - horse galloping and eagle flying overhead.

Forests are such classics that trying to think of a horse outwith them is difficult (for me).  

My ultimate layout is boring - incorporate an Arabian (stood snorting perhaps), Highland (rolling) and a GSD playing.  I think a beach would work well with GSD playing in water.