Writing an IMG File to Flash media
To write the USB IMG file to a flash card or USB pen drive you can use the dd command from a BSD or Linux command system. On a FreeBSD system, this command will write the image to the first plugged in USB device:
dd if=<path_to/img_file.img> of=/dev/da0 bs=5k
The device name will be different on a Linux system.
NOTE: The USB images are FreeBSD-UFS formatted, and will not show up as a viewable file-system under Windows.
To burn the image on a Windows system, you can use the physdiskwrite graphical utility.