I think you should state exactly how you feel, maybe something like: "Hello, I happened to be shopping for helmet spikes and came across your listing. I was a bit surprised when I noticed your ad with a picture that I personally took of my personal helmet with helmet spikes that I installed. If you would like to continue using the picture to generate revenue I feel that I should be compensated: how about 2 sets of spikes for permission to use the pic for this listing? In the alternative please cease and desist usage of this image for any and all purposes and please compensate me for the usage thus far with one free set of spikes. Thank you for your time and immediate attention to this matter."