This is functionality which unfortunately is not availble for Android.
Start by selecting the camera icon on your mobile.
Go to library
Select up to four (4) images/pictures
Upload these in the app
Go back to the camera icon
Push the arrow ('Back') in the upper left corner to re-enter the library.
Deselect the multi select function in order to be able to select additional images
Select up to four (4) new images and repeat the process.
Please refer to the video below.
(Push 'f' to view it in full screen, and 'f' again to reduce it.)