I've done it with both iMovie and with FCPX.....
With iMovie...you put all your clips in....and I believe you select them all, and change the timing to the fastest which I think is 0.1 sec....and it works just fine.
Similarly with FCPX...drop all images in...make into a composite clip, and then use the timing tool to reduce the whole clip to the length you wish...both work quite well.
To get the details on this...go search youtube...I found lots of tutorials there on how to do this. i Movie comes with OSX...so, it is a free tool to play with on the mac.
HTH,
cayenne