It’s to do with hiding malware/spyware in an image which ends up in your cache on device. I can’t go much further into details but all this takes is for you to visit a site that serves it via ad network.

Israel has been known to have some sneaky spyware in the past with Pegasus.

https://citizenlab.ca/research/how-discover-tech-turned-targ...

Article on the CitizenLab website: https://citizenlab.ca/research/how-discover-tech-turned-targ...

I don't know if an ad blocker protects against Discover-Tech’s Controlium but in general you'd be a fool to allow ads in your browser in at this point. The ad industry is pretty shady all round.