Sextortion: report on Sextortion

The risks
An ex-partner (or somebody else) posting or otherwise sharing explicit/intimate images of you, causing at worst extreme distress or at best, embarrassment.
Becoming the victim of financial or emotional blackmail.
If it is you that perpetrate an act of revenge porn, the very real possibility of:
Being convicted of a criminal offence, with a possible prison sentence of up to two years.
Causing considerable distress to your victim, with potentially tragic results to them and their family.
Do remember that however close you are to somebody, things may change and any photos or videos shot whilst in a relationship could feasibly be shared with others.
If you are a victim of revenge porn
Do not respond to blackmail threats.
Report it to the police.
If it appears on a website or social media site, report the images to the site, ask for them to be removed and the perpetrator to be blocked.
Do not be too embarrassed or ashamed to report revenge porn, as you could be helping yourself as well as other actual or potential victims.