From electowiki

This template is used by ImageAnnotator, version 2. It can be used to specify for an image the colors ImageAnnotator shall use for the note rectangles in cases where the defaults colors are not appropriate. To have an effect, a transclusion of the template must be placed on the file description page.

A note rectangle has two borders, an outer and an inner border. To highlight the active rectangle (the one whose note is shown), the outer border's color is set to the active color. All three colors can be specified with this template.


This would result in green note rectangles that would get a blue border when highlighted. All parameters are optional.