sharepoint user profile image not working, if app is running within teams tab

[DaFloDo]

we often use  .sharepoint.com/_layouts/15/UserPhotos.aspx within our apps, since loading seems to be more performant than using the 365-Users connector. 

Everything is working fine, when we run the app in a browser. Regardless, if we open the app directly or integrated as a MS Teams tab (MS Teams web version).

But when we use the MS Teams client application, the user photos are not displayed, using the SharePoint url method. 

We figured out, that the image urls are working, when we add a SharePoint Site as a tab. After the user has opened this SharePoint-Site tab within Teams, the user photos start working in the app hosted as MS Teams tab. Even after closing and reopening the MS Teams application.

Does anyone have an idea or a solution how to make the SharePoint user photos url work out of the box when APP is integrated as MS Teams tab?  

EDIT: Same problem seems to occur in web/browser, if a user did not access this SharePoint Site before ... 

[bcdautomation · Accepted solution]

We went down a similar path, 365-users can be slow or unreliable at times. Have you considered putting the images in a collection for your apps to use? Almost all of our apps clearcollect images onstart of an app, this can make the load time take a couple more seconds but its rock solid

[DaFloDo]

@bcdautomation thank you for your answer - loading and caching all images at startup is also our current solution - though it would be nice to load/access only images the user actually needs.

[bcdautomation]

We also use a sql table with a combination of a stored procedure and a daily power automate flow to store and update all of our staff images, which is nice for using in our software outside of the power platform