Ok lets go back up a bit.. You said...
I corrected you, because the offence requires more... my bold
(1)A person (A) who intentionally sends or gives a photograph or film of any person’s genitals to another person (B) commits an offence if—
(a)A intends that B will see the genitals and be caused alarm, distress or humiliation, or
(b)A sends or gives such a photograph or film for the purpose of obtaining sexual gratification and is reckless as to whether B will be caused alarm, distress or humiliation.
mens rea is a latin for a guilty mind.
This offence requires there to be an intent to cause alarm, distress or humiliation or obtain sexual gratification
In other words
sharing it is not enough.