1. Open a bunch of windows
2. Minimize one
3. Hover the mouse over its taskbar thing, notice there's no window preview [enable Window Previews].
4. Use an application switcher. Notice that there's either no thumbnail [Static] or a generic one [Ring].
Compiz should always have a preview. Either store the last on-screen drawing, and use that with some indication that it's old (say, lower saturation and brightness). Or, draw the window in an off-screen buffer and use that.
Mass closure: This bug has been untouched for more than six years, and is not
obviously still valid. Please reopen this bug or file a new report if you continue to experience issues with current releases.