USBImager is a really really simple GUI application that writes compressed disk images to USB drives and creates backups. Available platforms: Windows, MacOSX and Linux. Its interface is as simple as it gets, totally bloat-free.
Insert SD card into PC.
Click [Cancel] if prompted to format disk.
Note the new drive letter that has been created (ie. D:).
Select Image File (ie. piCorePlayer6.1.0.img).
Set Device to your SD card (ie. D:).
Write data on “Image file” to “Device”.
Writing should take about 14 seconds.
Exact time will depend on SD card quality.
Click [X] to exit program.
Click [Safely Remove Hardware and Eject Media].
Click [Eject SD Card].