Currently, our Personal, Professional, and Business plans allow for up to 600 images per 20 minute max video.
Keep in mind that Animoto videos stop when the music runs out or when there's no more imagery left to display -- whichever comes first. So, depending on the length and tempo of the song chosen, you'll want to make sure that there are enough images to see the song until its end, or conversely, that your song is long enough to show all the images that you'd like to include.
If your video doesn't come out right in terms of timing, you can always add or delete images, or change the soundtrack.
Note: Our new pacing features allow for more control over video speed and image transitions. For more info, check out our video pacing FAQ.