SharinPix has different way to upload images from mobile:

- using the online integration with our components in Salesforce mobile app

- using the offline integration with our SharinPix mobile App

Uploading multiple images from the roll works with:

- Any ways on iOS

- Only the SharinPix mobile App on Android

So when you are using the components on Salesforce mobile app under Android, you can't upload multiple images from the roll.

This is due to the webkit use in the current version of the Salesforce mobile App and its a known limitation of Salesforce mobile app as described here:

https://help.salesforce.com/articleView?id=000332906&type=1&mode=1

In a coming version, Salesforce should update the webkit integrated in Salesforce mobile app and get rid of this limitation at the same time.