sequence of multiple jpegs in fcp 6 and 7

I am trying to create a sequence of 100 jpegs, 15 frames each. I change still frame rate to 15 frames in user preferences but when I drag the frames to the timeline they are still the default duration of 10 seconds. If I select all the clips in the timeline duration is grayed out in the speed menu. I am having the same problem in both fcp 6 and tcp 7. Any ideas?

You'd have to remove your photos from the Browser first, then set the Preference, then reimport them. When you change the still duration pref, it does not effect stills already imported.