There are lots of way's to Reduce the Size of Xap file. like.
- Just put Multimedia files like images & video at client bin folder where the xap file is.
- this ways you will reduce the size of XAP file & take a fast loading.
- And also we can reduce size of XAP.. go to sliverlight project in Application ,Right click on it go "properties" see an option called -"Reduce Xap size by using appplication library chaching"
- We can move all the dlls (system dlls) out of the XAP files. They will be loaded on demand and will be downloaded from microsoft website/website of your wish.
- Split silverlight project into multiple silverlight projects. Load them when you need it. This way you can load what you need and also you save bandwidth.