The Facebook Messenger app offers users two very simple ways to send photos directly to their contacts. Users can either select existing photos from their Photo Gallery or take new photos directly from the Messenger chat window. If you would like to save the photos taken with the Facebook Messenger app, there is a simple way to have them auto-saved to your gallery.
In Facebook Messenger, tap on the Cog icon to open the Settings menu and then navigate to Data & Storage:
Tick the checkbox that reads Save on Capture - Save new photos you take in the app to your Gallery: Moving forward, photos taken with the Facebook Messenger app will be automatically saved to the Messenger folder in your phone's photo gallery.