Abstract: We describe a data visualization system based on spreadsheets. Cells in our spreadsheet contain graphical objects such as images, volumes, or movies. Cells may also contain widgets such as buttons, sliders, or curve editors. Objects are displayed in miniature inside each cell. Formulas for cells are written in a general-purpose programming language (Tcl) augmented with operators for array manipulation, image processing, and rendering. Compared to flow chart visualization systems, spreadsheets are more expressive, more scalable, and easier to program. Compared to conventional numerical spreadsheets, spreadsheets for images pose several unique design problems: larger formulas, longer computation times, and more complicated intercell dependencies. In response to these problems, we have extended the spreadsheet paradigm in three ways: formulas can display their results anywhere in the spreadsheet, cells can be selectively disabled, and multiple cells can be edited at once. We discuss these extensions and their implications, and we also point out some unexpected uses for our spreadsheets: as a visual database browser, as a graphical user interface builder, as a smart clipboard for the desktop, and as a presentation tool.