Above the description box there are a few tabs that says,
"add to" "share" "more".
click on more and the report function is right there. I've not reported before but I'm pretty sure the steps will be guided once you hit that button. On the matter of that, I believe that despite the photos being public domain and your voice being removed, the editing of the video is still Your work. The way everything is put together it is your effort. So it's probably still an infringement of your intellectual property.