The Facebook free mode without pictures and videos has been available for over a year and it has been used by thousands/millions of people. Facebook free mode is powered by Facebook Freebasics service that also allows you to access some websites for free using eligible Network.
Using “How to see pictures in Facebook free mode” you have to be using any of these networks viz 9mobile, Mtn and Airtel.

As we all know that Facebook free mode doesn’t show Pictures except Profile pictures, I’ve finally got a trick on how to view pictures when on Facebook free mode.

See picture in Facebook free mode

How to see pictures in Facebook free mode
REQUIREMENTS
*.An Android Phone for browsing Facebook free mode
*.Supported Sim Card without Data (9mobile, Mtn or Airtel)
*.Facebook Lite App We’ll be using Facebook Lite for this tutorial as it is working perfectly on it

*.Now, Download Facebook Lite HERE if you don’t have it on your phone.
*.After Installing the App Open it for about 2-3minutes then close it
*.Switch off your Data
*.Go to your phone SETTINGS > APP > Scroll down to Facebook lite and tap it then clear the data of the Facebook lite.
*.Switch ON your Data
*.Launch your Facebook Lite App
*.Enter your details and log in
*.It won’t load when trying to log in, just quit the Fb lite app re-open it again then it will load. When it opens you will see that you are on data Mode When it’s in free mode, Now all Pictures will be Visible.

Credits: https://techsload.blogspot.com/2017/12/how-to-see-photos-on-facebook-free-mode.html