Successfully made connections to the SharePoint On-prem using WAP and ADFS 

The users hits the external domain... https://mysite.contoso.com and gets validated by WAP and ADFS and directed to the on-prem webapplication on the LAN side: http://mysite.portal.com 

But the users mysite pictures and the pictures that users put in the newsfeed is not showing in the App

can someone please advise? 

Hi,

We are currently looking into this issue and will give you an update as soon as possible.
 
Thank you for your understanding and support.

Regards,

Hi,

Please help to collect the information below for troubleshooting:

1.Check whether the pictures can be shown when accessing my site from LAN(http://mysite.portal.com).

2.Capture the screenshot about the External and Backend server URL settings in WAP. If they are External URL: https://mysite.contoso.com, Backend server URL: http://mysite.contoso.com, please capture the screenshot of AAM settings as well.

3.Please right click on the picture, choose properties, and copy the link of the unavailable picture, and post the URL for the picture in your reply.

Regards,