We describe an image retrieval system we built based on a Zoomable User Interface (ZUI). We also discuss the design, results and analysis of a controlled experiment we performed on the browsing aspects of the system. The experiment resulted in a statistically significant difference in the interaction between number of images (25, 75, 225) and style of browser (2D, ZUI, 3D). The 2D and ZUI browser systems performed equally, and both performed better than the 3D systems. The image browsers tested during the experiment include Cerious Software's Thumbs Plus, TriVista Technology's Simple LandScape and Photo GoRound, and our Zoomable Image Browser based on Pad++. Also cross-referenced as UMIACS-TR-99-14