It appears that this problem has been fixed in Release 2.0.762, at least for my App. To check what Release your App is running go to Details - Versions - look at the most current under PowerApps Release column. Release 2.0.762 appears to fix the issue... Release 2.0.760 is the only release I was having the issue on. I am running my APP from "Edit on the Web".
Hope this helps, Marc...
Could you make sure to republish the app using 2.0.762? If the issue persists after that, could you make sure the images are at a URL that does not require authentication (for instance, you can load the images in a Web browser on an Android or Apple device)?
I am unable to reproduce the issue. Could you please open a support ticket using the URL below?
Once a support ticket is opened, you can work with the support staff to send us a msapp file. We'll investigate it from there. Thanks.
Here is a link acknowledging that the PowerApps is working on this issue:
Missing media on your apps? A quick fix.
problem statement: URL Ref images are showing when running powreapp on web, but not showing when running in Mobile powerapp client or on Windows power app client.
EditScreen1.image3 have an url that shows in powerapp web app.. but not in powerapp client on windows 10 or Iphone.
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