I am trying to convert an iso image so that I can use a usb stick to install ubuntu on my laptop. When I go to startup disk creator and click other the ubuntu iso file has no bytes so I cannot create a file to install ubuntu why?
If you just want to create a Live USB for Ubuntu, use unetbootin instead. Easy to use, either download from internet and create, or create from a local ISO file.
Otherwise, you can use
dd to do the same thing. For example
sudo dd if=/path/to/Ubuntu.iso of=/dev/sdX bs=8M.
First plug-in the usb device and run the following command
sudo fdisk -l
This will give you list of all the partitions you have. Check the partitions carefully. Most probably /dev/sdb is the usb one(if no other usb storage is plugged-in).You should see something like this(if it is a 8 GB pendrive)
Disk /dev/sdb: 8.0 GB,blabla.....
Now to make a bootable usb
sudo dd bs=4M if=/path/to/filename.iso of=/dev/sdb
BE CAREFUL with of option. If you carelessly put something wrong you will be doomed.