I just want to say that many know that manipulating a screenshot is an easy thing to do. For instance, I changed all the numbers on the above image just to prove my point. Again, I am not trying to say this is what the OP did. But I do hope there is a better way to prove that they changed their terms after you made your deposit, accepted the rules, and started wagering your bonus.
As Mahdirakib posted, OP is unlikely to edit the numbers because of the reason he already mentioned. Some other forum members already confirmed that they had 50x wagering requirements for bonuses. Now the wagering requirement is 90x. I understand that this member cannot do anything now since the TOS already changed. But, I do believe that you will agree with me that this is not a good practice.
I know 90x is too much already, but even if the casino decides to make it 100x, it is up to them. Nobody is forcing them not to change. But the thing is, they should update their pages asap and let the users know about the changes via emails. 30x wagering requirement is a standard already. A 50 and then a 90x is insane.