If you want to use an extension for Firebase Storage, i might suggest you use this one:
Alternatively, let me introduce you to the wonderful world of using Firebase RTDB and Storage with the web component:
Regarding images, where are they coming from in the first place, camera? These will be very big. Bear in mind that the listview will be displaying images, by default at @ 75x75 pixels, do your images need resizing?
The listview can start to "stutter" with long lists loaded from urls, you might then want to consider using a recyclerlist extension to build your listview: