This blog post will show some examples on how to use the QEMU image command.
Create a qcow2 image that has a maximum size of 20 GB.
qemu-img create -f qcow2 disk.img 20G
Display information about a qcow2 image.
qemu-img info disk.img
Increase the size of a qcow2 image to 40 GB.
qemu-img resize disk.img 40G
The Windows version of QEMU was used for writing this blog post.