I'm still pre-coffee this morning, but here's how I have it worked out:
OP
Friend A
Friend B
Friend C
Girlfriend of C
Person X (from dating app)
OP showed A a risqué pic of X. A showed B. C and GF of C got pissed at OP for showing it. OP, in trying to discuss/clarify with C and GF of C, learned that GF of C didn't have OP's number and handed phone to GF of C to get their number. GF of C read a text from A or B to OP that called GF of C a twat.
GF of C, in addition to being pissed about OP showing A and B a risqué pic of X, is also now potentially pissed at OP and A or B for calling them a twat.
OP is undecided if they are pissed at GF of C for reading that text.