I'm a programmer and amateur radio operator.
Fediverse @lemmy.world How to Kill a Decentralised Network (such as the Fediverse)
Programmer Humor @programming.dev Stop doing Computer Science
Programmer Humor @programming.dev Intuitive UI
Programmer Humor @programming.dev Monitor Alignment Alignment Chart
Programmer Humor @programming.dev The difference
Programmer Humor @programming.dev 0.30000000000000004
Programmer Humor @programming.dev Programming Languages as Essays

Unfourtunately, I couldn't find a source stating it would be required. AFAIK it's been assumed that they would use perceptual hashes, since that's what various companies have been suggesting/presenting. Like Apple's NeuralHash, which was reverse engineered. It's also the only somewhat practical solution, since exact matches would be easily be circumvented by changing one pixel or mirroring the image.
Patrick Breyer's page on Chat Control has a lot of general information about the EU's proposal.