The medium of collage supports the visualization of meaningful event summaries using photographs. It can however be rather tedious to author a collage from a large collection of photographs. In this work we present an approach that supports efficient construction of a collage by assisting the user with an automatic layout procedure that can be controlled at a high level. Our layout method utilizes a pre-designecl template which consists of cells for photos and annotations applied to these cells. The layout is then filled by matching the metadata of photos to the annotations in the cells using an optimization algorithm. The user exercises flexibility in the authoring process by (a) maintaining high-level control through the types of constraints applied and (b) leveraging visual emphases supported by the layout algorithm. The user can of course provide fine-grained control of the final collage through direct manipulation. Off-loading the tedium of collage construction to a user controlled yet automated process clears the way for rapidly generating different views of the same album and could also support the increased sharing of digital photos in the form of compact collages.