Legal Question in Intellectual Property in Pennsylvania

Re: Use of copyrighted/patented material

You're probably in luck.

As long as one doesn't reproduce the images but just uses each decal as it was bought, the "first sale" doctrine of copyright law would generally permit someone to affix such an image onto another product.

Unique questions might arise if the decals contain special kinds of images, e.g. a celebrity who might object to having his likeness on your candles. Or someone might hypothetically have a patent on a candle decorated with decals, so that the product might infringe a valid claim of a U.S. patent. That's possible, but unlikely.

In general, once a copyrighted work is sold to a first customer, the copyright holder cannot prevent the customer from transferring the work to someone else. It's okay to buy a printed book and then to re-sell it, or give it away, and the copyright owner cannot prevent that. (On the other hand, the way that digital images are typically distributed is not by sale but by license, and that gives rise to a lot of other issues.)