I decided to enable the no- right-click plugin for WordPress so that no-one can use a right-click to copy my images. I don’t need to protect my income by making sure no-one is using my images, but I don’t particularly want other people using them without asking for permission first.
You can do a Google search for an image by dropping the image onto the image search box. I tried that with an image and found it in a few places on the Deviant Art website, but it was linked to my original image, which is okay. It’s also possible to put an invisible digital watermark on images using a service such as that offered by digimarc. Your image, and derivatives of it, can be more easily tracked with a digital watermark.