I just opened Photobooth wishing to use the Pop Art effect and discovered that only one of the four split screens (red, green, yellow, in the top left-hand corner) is now working. The other three-quarters of the main screen is plain yellow. Hardly the end of civilisation but a bit annoying!

The only thing I've done that I think could have affected it is upgrade my OSX (following links from an automatic search for software). It's currently running Mac OS X Version 10.4.10.

I've tried rebooting the application and restarting my machine but it's done no good.

Any constructive suggestions gratefully received!