Image picker - image upload availability - turning on and off

There is an option to upload a new image via the image picker in hippo, but there is no option to turn this feature off (and on again).

The main reason for this request is that users who upload an image via the picker do not have the ability to also fill in alt text, titles and such. This has the potential to create a dirty work environment where users of the CMS have the ability to ignore these fields in the Images/media tree/tab.

(This is defined in the hippo-cms-xinha-integration - class: ImageBrowserDialog)