Hi,
I just would like to introduce you to my new app.
With this module you can easily drag&drop multi-Files into a form-view. You can also add Screenshots with CTRL+V. It only works in "Read"-Mode.
Download link: https://apps.odoo.com/apps/modules/11.0/drag-and-drop/
Lets give it a try. Please report me bugs.
Best regards,
Andy