1, Locate your php.ini.
2, Open it in a text editor
3, Search for upload_max_filesize.
4, Change 2M to something else, for example 20M.
5, If the upload_max_filesize is larger than post_max_size, you must increase post_max_size so that it's bigger than upload_max_size
6, If the value of post_max_size is larger than memory_limit, you must increase memory_limit so that it's larger than post_max_size.
7, Save your changes to the file.
8, Restart your web server.
http://www.squirrelmail.org/wiki/AttachmentSize
