Do I need to search citation sources for a rather generic graphic that I have drawn myself?
If you create an image yourself that is not modeled after/derived from someone else's, you don't have to go out of your way to learn if someone has created a similar image.

For example, if I create a flow diagram of a common process for my paper, it's likely that many other papers have a similar diagram (because the technique of using flow diagrams to illustrate a process is pretty standard). That's perfectly OK as long as I didn't intentionally copy them.

(As always: if the technique of visualization or the data content of the image is not general knowledge, cite it.)