There is only one file type that uses the .WBZ extension:
Webshots Download Picture File
File used by Webshots Desktop Connect, a program used for viewing, organizing, and sharing digital pictures over the Web; contains one or more downloaded images in a proprietary format; used to package images for download so that they are viewable in Webshots Desktop Connect.
NOTE: Webshots Desktop Connect was formerly known as Webshots Desktop and was owned by AG Interactive before being acquired by Threefold Photos in 2012.
Updated: August 15, 2015