Firebase Storage on Android and iOS

[TIMAI2]

There may be another approach, as shown by @Anke here:

Uploading image on iOS

I was able to upload images to my server using a simple app on my iPhone. Unfortunately, it is not possible using the WebViewer, but it works using the standard browser. You need an uplaod_formular.html and an upload.php script. Both must be in the same directory on the server. The appropriate read and write permissions must also have been set up there. The upload form is then called up using Activity Starter.

and loosely based on this:

METRIC RAT AI2 - Firebase Storage with Webviewer

and this:

How to upload image to firebase cloud storage from input field?

I have a working html file you can test if you wish...