When you upload artwork to your FASO account, the last uploaded piece of the day gets featured in the next day's Daily Art Stream (DAS).
People can buy your art directly from the DAS by clicking on the Learn More or Purchase button.
The Learn More or Purchase button will automatically show below your art (right hand column) as long as you:
The image will be placed in the Medium-size image section of the DAS. This section is specifically for Gold Plan members who have eCommerce enabled and have listed a price on the art.
For more info see:
The Daily Art Stream Explained, How to Be Included / Images in 3 Sizes