Hi wesselrossing,
I don't have a milestone, but I do have 2.2 on a Nexus One.
I tried your app.
I did 2 time-lapse sequences. App seemed to work fine.
I checked the gallery, but couldn't see any images.
I checked the SD card, and I can see a TinaTimelapse folder, and in there are 2 folders, one for each of my time-lapse sequences. And those folders have the images that I expected to find.
Personally I think the Gallery app on the phone is a buggy piece of crap.
If I take photos with the standard camera app they never appear in the gallery straight away.
Sometimes I'll go in and out of the gallery several times, hoping it will refresh, but it doesn't.
Pictures turn up eventually. But I'm not sure how to make it work properly.
This was a problem in earlier versions of Android as well.
I have a camera app in the market (SoundCam) and I had complaints about the images not appearing in the gallery. When I asked people to check the SD card, they found the images were there, just not shown in the gallery.
It looks like your app is working, but you're suffering from bugs in the Gallery app.
You could ask your users to check the SD card to confirm the pics are there, just in case there are other problems specific to the Milestone.
If you work out a way to get the Gallery to refresh I'd be very interested in hearing about it.
Mark
p.s.
I went back into the gallery about 10-15 minutes later, and the time-lapse images turned up.
I found a discussion here:
http://code.google.com/p/android/issues/detail?id=7575