contao/core — pull request #5172 by tristanlins (2012-12-20 11:42:16+00:00)
Title: Prevent oversizing of colorbox lightbox.

If a source image is bigger than the viewport, colorbox will oversize the lightbox to fit the image size. You have to set a maximum width and height to prevent this. (Scaling is enabled by default, but no max width and height is set by default).