Try looking at greatbigcanvas.com...they have a huge selection in different styles. You can get just the canvas, a floating frame, or prints framed (black only) or unframed. Prices are pretty good--I just bought a few pieces for newly remodeled downstairs. Also check out overstock.com, art.com and for original art etsy.com. 20x200.com is also good but last time i checked the site was down for "remodeling."

Have you considered something like a white orchid on the left edge of the vanity, rather than artwork above the toilet? It's hard to get a sense of the room from one photo but I'd be a bit concerned that artwork above the toilet would interfere with the pleasing arrangement of mirror and sconces. It might be a lot of stuff for that one fairly small wall.

I chose one of my photos of the marsh and river and had it transferred to canvas. Groupon puts out an offer about once a month for a canvas transfer deal and they execute them very well. You may want to consider that. I never tire of it.