Have you have written a custom placeholder and wanted to allow the user to select an image from the resource gallery? Well, the AuthFormClient.js has several Javascript methods that allow you to do just this.

WBC_launchImageGallery(strPostingQueryString, strPhName, strPhType, bAllowUpload)

There are lots methods in the MCMS framework files that do all sorts of cool things (and even some mysterious things), so check them out.