When I discussed some time ago why minimized windows have an apparent size of 160×31, I explained that the minimized icon is a miniature title bar, but I managed not to explain why the values are exactly 160 and 31. The width of the miniature title bar is determined by the iWidth member of MINIMIZEDMETRICS structure. You can retrieve and change this structure with the help of the SystemParametersInfo function. (Use the SPI_GETMINIMIZEDMETRICS and SPI_SETMINIMIZEDMETRICS flags, respectively.) Some people will mention the MinWidth registry value, but those people are wrong. Notice, for example, that messing with MinWidth requires a logoff cycle, whereas using SPI_SETMINIMIZEDMETRICS takes effect immediately. That’s because SPI_SETMINIMIZEDMETRICS updates the internal state variables, whereas whacking the registry just change a value in a database that nobody pays attention to once you’ve logged on.

What about the height? That’s just the height of a caption bar, which you can adjust from the Appearance tab of the Display control panel. (Programmatically, you can use that helpful SystemParametersInfo function, this time using the iCaptionHeight member of the NONCLIENTMETRICS structure.)