I don't see any harm in it. The instructions for doing so are here ...
If you have a Paypal account that accepts payments for goods (I have such an account), you can easily sell anything you want directly from this forum. You simply have to login to Paypal, create a button for the item you want to sell and then click on the 'Email' link provided by Paypal. Use the provided email link with the Paypal icon link -

- underneath the details of the item you want to sell. That is all there is to it.
By they way you need to be logged in and in the 'FOR SALE' forum else the Paypal icon will not display.
By using the 'Upload a File' you can create a mini-gallery. You upload an image and choose to create a thumbnail along with. The smaller images are the ones that are used by the gallery script. See below as an example (click on an image).
More detailed instructions to follow.