When ever I sell on eBay I always use my own pictures and my own description of the item I am selling.
Using or copying someone else's work is just not good business sense.
I have had times when people have actually copied my pictures and description , after I found that out , I started to use very unique HTML disruptions and encoded my pic`s so that they would be useless to anyone trying to pirate my work.
When ever you work on the web , you will always take a chance that plagiarism might happen.
As a writer , I strictly oppose any type of copying.
The best thing to do when selling on eBay is to take your time and write a proper and true description , and think about a good hook or tag that will make the customer want your product.
Always be truthful , never give false info , that is my practice and so far it has worked just fine.
I hope this info helps !!
Take care,
Gary