Redmine

As it is already possible to upload files by using drag n drop, it'd be a great UI improvement to immediately generate the markup for an image when dragged into a textarea. We have seen this feature at github and think it would be a great UI improvement to redmine. For example, if you drag an image into an issue's description field you'll get !image.png! (if formatting is set to textile) or ![](image.jpg) (if formatting is set to markdown) at the current cursor position.

I am attaching a patch that introduces this feature into redmine. Allowed are all image file types that are listed in redmine's mime_types. The behavior remains the same for all other file types / non-image file types.