Anytime a section of TOC is updated, the picture stored in that section gets copied into my TOC.

[brap367]

I have a field that contains an image of a graph and anytime I update the TOC, that graph copies itself into the TOC.

[JimP]

That is probably because you have the image assigned to the TOC style (either Heading 1, 2, or 3). To fix it simply apply a different style to the image then update the TOC again.