The company may not care, but the gov definitely does. And if you don’t report then you could be in serious legal jeopardy. If any fragments of that image are still present on your machine, whether it came from the company or not, you could be held accountable for possessing csam.

So screw the company, report it yourself and make sure to cite the company and their lack of a response. There’s a Grand Canyon sized chasm between “offensive content” and csam.