There’s an easier way to image your SD card! Check out the “Getting Started” guide for a cross-platform guide.
Open up the folder where you downloaded the ev3dev image file
Right-click and select Extract Here to uncompress the file
This will extract a single file with the same name minus the
.zip). Right-click this new file and select Open With > Disk Image Writer.
Make sure your SD card is plugged in and select it from the list, then click Start Restoring….
Heed the warning. This is your last change to backup any files on your SD card. When you are ready, click Restore.
Yes, this requires root privileges, so type in your password and click Authenticate
Wait for it… This could take a while depending on the speed and size of your SD card.
When it is done, click the eject button and remove the SD Card.