It was definitely not convenient during development. When I was testing for IE9, every change in the code needed to be encoded to the PNG image. But having an

It was definitely not convenient during development. When I was testing for IE9, every change in the code needed to be encoded to the PNG image. But having an automate build script really helped speeding up things. YUICompressor caught all the major bugs during the build process so as long as my un-minified/unencoded scripts worked, I was pretty sure that the PNG version would work as well.