Rattle sound coming from starter/trans area!

Ok it only happens when I start the car. You never hear it again. It sounds like you took a soda can and put some rocks or pennys in it and was shaking it!. I believe its the starter as that you only ever hear it when you start the car. But its close to the sound of a pulley squeal too. Any advice is helpful advice!
 
Any work done on the car lately that involved removing the starter and, if so, are you sure that the starter was re-installed properly (all bolts, all bolts torqued/tightened etc)?