Just checked the R/air app. It notes that this ID rigmarole applies to 3rd party sellers AND bookings made on the Ryanair app.
I got as far as ‘Pay now’ on the app and didn’t see this ID thingie. 
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Maybe it comes up once they’ve got yer dosh…
That’s strange. I just created a new dummy account and got the same as you, no request for any passport info up to paying. The OP did say they were booking direct with Ryanair, but looking again they say that it was at the stage where they entered their passport details that the problem occured, but you don’t need to do that until after you’ve booked and it’s never asked me for a photo. Very strange.
Glad you have confirmed my reply previously about my sister booking recently on their official UK website and not needing to give any photo ID.
No idea what the problem is,they have all my passport details,number,exp date and all my personal details when i was ordered to create an account,then when i selected all my flights and went to pay,a box appeared saying that i hadn,t verified my id,the only option they have is to try and dangle your passport in front of a pc camera with half the box missing,anyway have given up with them and have booked with Easyjet.