Remove an image through subtraction?
It is possible and works in a similar manner. What's different is that normal pixel values in video are always positive, whereas it's normal for audio to go both positive and negative several thousand times per second.

If you have a copy of the axes without the spectrum, you can overlay the image with the spectrum on top of the image of the axes and set the blend mode of the spectrum image to "difference." That will subtract the image of the axes from the spectrum image and leave black where the axes were.

If you don't want black, but some other color, you can use an image mask that sets the axes to an alpha value of 0 and the rest of the image to an alpha value of 1 (or 255 if you're working in 8 bit per channel mode). Then put some other color underneath the masked footage.

EDIT: I forgot to mention that the image of the axes alone should be black wherever you want the original image to come through. (Because you're then subtracting 0 from the original image in those areas.)