I want to do a nice effect that would do something like this:

So far, I made a separate layer in photoshop for each colour, and I want these to slowly fade in and out. The problem is, however that each blob is about 140KB if I use PNG. Is there a better alternative like doing this in vector and blurring it in jquery? Thanks :))
Few minutes of work below, but I still don’t find it as a best solution… I’ve overcome blur problem with simple gradient – faster… Fading should be JavaScripted.