I have created app that use resource as SharePoint library where images are strored. I am showing these images in PowerApps using Gallery control. When I shared this app with other users few of them were able to see the images in Microsoft Edge browser, few in both Chrome and Edge but few could not see them in either of the browsers.
As an alternative solution, I created another SP list data source and a Hyperlinkcolumn (Formatted url as Hyperlink) within it. Then copied URL link of the image files in my SP library, created corresponding record within SP list and put the copied URL link within the Hyperlink column. But issue still persist.
I got below response in other posts
"If you share your app with other users in your Org, when they run this app, they may not see these images within the Gallery. It is an known issue with images stored in SP Library that pictures that need authentication on SharePoint are not supported yet within PowerApps when running an app in Mobile device or other users run this shared app."
However if this is the issue then it should be consistent across all users, why it is working for some users. The edge browser version is same for the user where it works and not work as well.
I have a number of blogs posted on my website that levaging different techniques to render photos stored in SharePoint document libraries in highly compressed formats which work within web clients as well as in the context of the PowerApps client from the mobile app stores. I'm pretty certain you'll find a solution on this site that works for your requirements...