Django-Filebrowser - IOError due to directory in image field

I'm using django-filebrowser, with a model field declared as

image = FileBrowseField("Image", max_length=200, blank=True, null=True)

and using the image in a template with

{% version_object obj.image "thumb" as img %}

In admin, the filebrowser allows the user to select a directory in place of an image. When this happens (accidentally), the version_object template tag above raises an IOError: "[Errno 21] Is a directory".

This is pretty disastrous as it breaks the whole page the image appears on. How can I...

1. Make the template tag fail silently rather than breaking the page, and
2. Prevent users from selecting anything other than an image when populating the field?

The "SELECT_FORMATS" setting sounds like it might help, but the documentation is unclear:

Set different Options for selecting elements from the FileBrowser:

SELECT_FORMATS = getattr(settings, "FILEBROWSER_SELECT_FORMATS", { 'file': ['Folder','Image','Document','Video','Audio'], 'image': ['Image'], 'document': ['Document'], 'media': ['Video','Audio'], })

When using the browse-function for selecting Files/Folders, you can use an additional query-attribute type in order to restrict the choices.

I don't understand how (or if) this setting applies to the admin interface.

Try setting the format attribute on your field

image = FileBrowseField("Image", format='image', max_length=200, blank=True, null=True)