[PROBLEM] How to restore IMG backup file

[QuadCorei8085]

Tricky question: as the SD can corrupted i moved (copied) the XBIAN to an external USB partiotion (sda1) right after installation, using the built in xbian-config/"xbian copier".

After finished configuring and installing my XBIAn i've made an IMG with the same "xbian copier".

How can I restore the IMG to sda1? dd?

[edit]:
Also: how can a simple power outage corrupt my external usb HDD so much that XBIAN can only boot up to "the blinking cursor"?
Happened to me 2x so far. Really annoying to reinstall the whole system after every power outage.