Image Optimisation

Hi there! I am paying for image optimisation via Smush Pro, but when I run a Google page speed test on my site, it still recommends the following images need a image plugin to optimise them: background2.jpg, test-slide-anita.jpg, background-clouds-2.jpg. I am just wondering why these images aren't optimised via Smush?? And if this can be fixed :smiley:

I am also considering swapping my server across to WPMU. What info do you have on this, and how do I make sure its a stable server? Ta