Different size of .swf files

I have a flex project with two .mxml files. The开发者_开发知识库refore, there are two .swf files in the bin folder. The size one of them is 500Kb and another 3Mb. Why are they so different? I assume some files with embedded images are not included in the first one. But why? All files in one project in flex builder.

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There's another question about analyzing the size of the SWFs. It has an answer with a tool that lets you easily visualize what exactly it is that takes so much space in the file, based on a report made at compile time.

Any way to analyze the size of a SWF built in Flex?

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Every Flex application uses some aspects of the Flex framework, which is a relatively large set of ActionScript classes that define the infrastructure of a Flex application. The larger file has the flex framework merged into it. The smaller one doesn't. Since both files are in one project, it is probably using the framework embedded in the larger file. To reduce file size use framework RSL (runtime shared library). You will find more about RSLs here.