You can order all your photos in the project panel then choose "automate to timeline". In CS4 you can alter the duration of a seleted group of clips all at once to any value you like.
how to delete all gaps / rippels between my photos in the timeline ?
I don't think that's possible. It'll be one gap at a time.
Some NLE's, like PrElements, have a "close gaps" function. In PrPro, you will want to zoom in to about the frame view level on the Timeline, hit Home, then do a PageUp to step Clip to Clip, looking for the gaps. When found, there are a couple of ways to handle them, but with stills, I'd just drag the Tail of the preceeding Clip, or the Head of the following Clip, to close them up.
When you do the PageUp, or PageDn, you can watch the CTI (Current Time Indicator) to see if it jumps smoothly from Clip to Clip. If it "hiccups," or "stutters," you have likely found a gap, even if you cannot see it. This can happen with even the highest horizontal zoom level.
Thx for all your answers I found a very easy way now .... When I select all the photos in the timlie i right click on them an then select speed / duration and than select my prefered duration and tick "Ripple Edit, Shifting Trailing Clips"
Great and thanks for reporting. I actually learned something, as I have not used that method.