- This article or section documents the current version of Scratch (version 3.0). For this article in Scratch 2.0, see Project Compression (2.0). For this article in Scratch 1.4, see Project Compression (1.4).
In Scratch 3.0, the maximum project size is 318 gigabytes. If a project reaches a high file size, there are several ways to reduce the size. However, each costume and sound has a limit of 10 MB each. For example, projects may have as many sprites as desired; but the sprite must be under 10 MB. The project.json file, which contains the project's code, also has a limit of 5 MB.
Sprites and Scripts
There may be big actions that are repeated multiple times, which can take up lots of script space. This can be fixed by creating a custom block or using broadcasts.
Backdrops and Costumes
There may be backdrops or costumes that are not being used. Deleting useless backdrops and costumes will free up space.
Bitmap images can be compressed. If they are from a local computer, they can be compressed externally using a tool like TinyPNG and uploaded.
If a bitmap costume can be shown as a vector image, consider using a vector costume as vector images tend to take up less space.
If this is not possible, the image can be scaled down and back up, but that may cause unwanted pixelation.
Vector images can be further reduced in size by removing (and possibly replacing) excessive details such as windows on a building or fur on a hairy monster.
Unused sound files can be deleted because they take up a lot of space. Common sounds to remove are the other sounds included by default in all sprites.
If a project contains sounds are from one's hard drive, then they can be replaced with a compressed version. One way to compress sounds is to convert them to an MP3 file using this site.