You might want to check out the Scratch Suggestions page! There's a suggestion like that there which you can support.
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The limit's only there so people with slow internet connections don't have to wait forever for the project to load. In fact, most Flash sites have a 10MB limit! The problem is that Scratch projects are massive, especially when compared to Flash files.
If you're having problems uploading because of the filesize, try this:
1. Go to the Edit menu.
2. Select "Compress Sounds..."
3. Choose a sound quality. Remember, the lower you make the sound quality, the smaller the filesize will be, but it'll make it sound a lot worse in exchange. "Normal" is probably your best option.
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I've heard that the 10 megabytes limit is because of Java capibilities - and I've also heard that in Scratch 2.0 the limit might go up.
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To paraphrase a misattributed Bill Gates quote, 10mb ought to be enough for anybody.
The thing is, even some projects that are under 10mb still take absolute ages to download, or even to load, for that matter. Like this one. If you try to download that on the average computer from 10 years ago, it'll take quite some time. So basically the limit is there 1) to allow people with slower computers and connections to still be able to download projects, and 2) to keep the server that holds all our files online from blowing up.
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