Just a note: MySQL don't have a real Blob field intented to store binary files (the MySQL blob is a Binary Version of the Text field type). You're sugested to store the media files in disk and keep the path to your file in the mysql record.
Usually it would. If you have everything correctly configured and coded, most times you would just use the media files directly from the directory where they are stored.
It really depends on what you're doing and how you're doing it.