I have written a simple redirect server/image viewer that uses google tag manager to track the IP address of the user clicking on the link or views the image. I use this mainly to track romance scammers that constantly contact me and claim to be in love.

E.g. this is a “captcha” I send them and have them read it to me back: https://r.lehmann.cx/xbmxzg

It uses Google Tag Manager to get the client tracking, it would work with Piwik tag manager as well. I currently use Google Analytics and Piwik to track, that is not really necessary, a simple image beacon would be enough, also you can simply look at the server access logs of the redirect url and leave out the tracking tags completely.

For images I either use my photo gallery or image upload at teknik.io, that works with any image hosting of course, I could even put images locally to avoid the crossdomain link.

The script is a simple php script, if anybody is interested I can put that up as open source. It is basically a simple clone of grabify.link