GeoPixels surely doesn't make reporting violations easy...

By default, you're in Action mode (painting). Any clicking on the map will attempt to draw, and reporting is unavailable until you turn off the Action mode.

1. Click on the Tools menu.
2. Click the Paint icon, to switch mode to Inspect.
3. Menu will close when you click, so you might not notice any effect at first.
4. To check if it really switched the modes (you could misclick after all), open the Tools menu again. Ensure the icon is now 'looking-glass', which indicates the Inspect mode, but do not click that looking-glass icon, or you will go back to Action mode.
5. Now click any painted pixel, and a popup frame will show up. It will say who drew it, what are the coordinates, etc. It will also have 'pin' (favourite) button on the top left, and a 'flag' button on the top right.

This "flag" button is used to report things to mods/admins.

Also, it's worth noting that the 'flag/report' button is not available if you do not have account and are not logged in ... but the whole map, and all pictures drawn by anyone are available for viewing by anyone who pressed "yes I'm 18+" button.

Very, very confusing UI design!