You'll also find art customers will usually pay more for a good piece of art. Most of your current portfolio have a artistic touch so they should sell pretty well. I would continue focusing on uploading stuff you have that is more artistic than stock. And technical quality is still an issue for art, faa will check all sales for printability before the sale is complete, ie, noise, sharpness, etc. If there is any print issues with your image, they will give you a warning and up to 24 hours to correct it, otherwise they will cancel the order.
-W