Tracing an image from the internet

There may be some type of encryption in the metadata procluding any sort of tracing or modification.  Images on the internet are copyright protected and, even if there is no such image protection, you still need permission to do what you are attempting to do.  Did you purchase a license on that image?  Does the license give you rights to create derivitives from that image?  If you downloaded the actual jpg from the internet, you've already infringed on the owner copyright.  That might be why you cannot trace it.