Updating svgz images

A while ago we updated several wallpaper svgz images. How did we do that --- what software was used? I updated several png images in GIT hash 49c4ccfe to fix some branding. I would like to update a related svgz, but I don't how. The specific file to update: tdebase/kcontrol/pics/crsc-app-background.svgz. View tdebase/kcontrol/pics/cr128-app-background.png in the latest GIT to see how I updated that image. The svgz should look the same. Thanks! Darrell