I'm using the ImageField field type in the admin for attaching various images to pages etc but the current implementation which just shows a list of filenames in a drop down box isn't very ideal. Has anyone created a better field type which allows image thumbnails to be browsed instead of just viewing them by name?

I couldn't see anything anywhere but thought it best to ask before I set about creating something myself. User defined image cropping (vs resizing/auto cropping on center which can be done in the template) in the admin would be useful as well.