I have just made a slide show, 3 minutes, some music and 3 slides.
I exported it for youtube with 10fps.
The file ended up with 35 Mb.
Isnt there an export option that allows less fps resulting in a much smaller file size?
What frame size are you exporting to?
There is likely a way to get it a little smaller. I will play around with it and see what I can come up with.
Post a screen shot of your export settings. We might be able to spot a problem.
Edit: Well, at 1920X1080 a 3 minute slide show starts to fall apart at less than 30MB or so. The bitrate drops to the point where the images are not clear. Anything under about 1Mbps is just too noisy. I used H.264. There might be a better choice for slideshows.
I am impatient person and cant wait 15 minutes.
Now I use export H.264, reduced the target bit rate to 4, key frame distance to 144, 10fps and a three minute movie size came down from 105Mb to 10Mb with reasonable 720p image quality.