I'm using ubuntu 14.04 (x86).
I was trying to create a bootable dvd disk for Ubuntu 13.04. I have downloaded the image file (.iso) and successfully created a bootable USB using Startup Disk Creator. But when I tried to do the same with a 4.7 GB DVD, the Startup Disk Creator is showing DVD's capacity as 2KB and Free Space as 0.0B. It also shows a message "The device is not large enough to hold this image". 
Ubuntu – Why Startup Disk Creator is showing a blank DVD’s capacity as 2KB where 4.7 GB is free
14.04livedvdmountstartup-disk-creator
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Best Answer
Because the app is only for usb & sd drives, not dvd's
"Startup Disk Creator converts a USB key or SD card into a volume from which you can start up and run Ubuntu"
To burn your iso to disk, right click on it in file manager, and choose Write to Disk.