I sell a graphics design gig here on fiverr (amongst other things). The buyer provided me a simple jpeg image. They have asked me to copy the image in Illustrator, but alter the little icons that are throughout the image. So pretty much the new image that I will be delivering will contain the exact same colors and overall design, but the little icons that are scattered throughout the image will be different. Pretty much they are asking me to create a derivative work. How do I know that the provided image is royalty free? Would I be held liable if the new image infringed on the copyright of the image provided by the buyer? Thank you for your help!