I hv just upgraded my Snow Leopard to Mavericks, resisting the bigger jump to Yosemite or EC. Afraid may slow dn my com. Is this the downside of the newer OS? When a folder contains pictures, at the bottom right corner I can't find any zoom slider to enlarge the picture. In SL there is this slider. Or need some kind of configuration? If by default it isn't there, than it is really a big big setback. More like one step forward 5 steps backwards. Hope I'm missing something.