The physical context of architectural design includes large workspaces, typically drafting tables covered with piles of images and sketches. We are investigating if and how a large computerized workspace can be integrated usefully into such a design environment. To this end, we compared a large computerized desktop (digital desk) to a standard desktop computer and a small tablet environment for two typical architecture design tasks: sketching and image sorting. For the sketching task, the participants' preferences were evenly divided between the digital desk and the tablet. For the image sorting task, the desk was the least preferred environment, and produced significantly higher sorting times and more mistakes. Investigation into the causes of this difference yielded several interesting findings, including: the height of the participant was significantly associated with their speed on the sorting task, the larger image size available on the desk compensated for its poorer resolution in subjective preferences, and the quality of the alignment of the pen was an important factor both for preference and scoring results in the sketching task. Highly responsive pen input devices seem critical for user satisfaction not only for sketching, but also for image sorting; the effects of large display spaces are difficult to isolate from the limitations of input device. This paper elaborates on these findings and considers the implications for the design of user interfaces for image manipulation, in particular interaction techniques appropriate to using pen-input with large display surfaces.