Bluri can apply a blur effect on a image you pass as an argument. I use bluri to blur my i3-lock screen since ´convert´ was not fast enough.
To use bluri you will need a working go installation. Also you need to install the package this program is depending on:
go get github.com/disintegration/imaging
cd bluri
go install .
bluri -f=path/to/image.png -b=blurfactor
