diff --git a/suckless/virtual.mdwn b/suckless/virtual.mdwn
index 33e1039ca63cc8396b1504c9744dce930f704942..fbcc13b5fb505d3900c019cad71686c9828a6360 100644
--- a/suckless/virtual.mdwn
+++ b/suckless/virtual.mdwn
@@ -92,3 +92,8 @@ Mounting guest images:
 
 * [Mounting raw and qcow2 VM disk images](https://alexeytorkhov.blogspot.com.br/2009/09/mounting-raw-and-qcow2-vm-disk-images.html) using `losetup` or `qemu-nbd`.
 * [guestmount](http://libguestfs.org/guestmount.1.html) from [libguestfs, a library for accessing and modifying VM disk images](http://libguestfs.org/).
+
+Image optimization:
+
+* [Tip: Making a disk image sparse | Richard WM Jones](https://rwmj.wordpress.com/2010/10/19/tip-making-a-disk-image-sparse/).
+* [How to convert a non-sparse image to a sparse image – Patrick's Blog(2)](https://blog.laimbock.com/2013/10/31/how-to-convert-a-non-sparse-image-to-sparse/).