@Benard Regarding US law, the inventor "must use his knowledge and ingenuity to produce a new and useful thing or result, or a new method of producing an old thing or result" (Lane-Fox v Kensington & anor, (1892) 9 RPC 413. The invention must be for a useful art as distinct to a fine art, so artistic or musical works are not patentable even if new and original. Amazon seems to have patented a certain set-up, but that's not stopping other photographers from freely using this method.
@dillonk Patent trolls can use this to sue online retailers who have such pictures on their site. Photographers can easily use a different grey background to get away with this. Anyway it remains to be seen if this would actually be enforceable.