I was trying to convert .svg files to .png. No problems with that, but when doing so I lost the transparency of the originals. Not that that really mattered because I had a white background-color anyway, but I had to find out!
First be sure to install imagemagick:
sudo apt-get install imagemagick;
And use `convert` to convert:
convert +antialias -background transparent \ media-playback-start.svg media-playback-start.png;