MySQL offers four blob types, which differ only in maximum size. They are tinyblob (256 bytes), blob (64 kilobytes), mediumblob (16 megabytes) and longblob (4 gigabytes). There are also the binary and varbinary data types, which are the same as char ard varchar, but store binary strings. See http://dev.mysql.com/doc/refman/5.0/en/blob.html and http://dev.mysql.com/doc/refman/5.0/en/binary-varbinary.html for more details.
This was first published in January 2007