I’d like to allow users to add multiple attachments to a form submission. In the form, they click the attachment button (the repeating group off to the left will display the pictures uploaded after they attach them):

The attachment button (above) creates a dropdown as shown here:
After the user clicks the “attach” button above, my app enters these images in a Thing called “Attachments”, but has no way of associating the Attachments with the form submission (the form will create an entry in a “Location” Thing) until they click this submit button to create a Location entry:

My question is: how can I attach multiple pictures to a form submission before submitting it (i.e. before creating a Thing entry to which the attachments can be associated)?

