Board Thread:Support Requests - Getting Technical/@comment-31246436-20161122151009/@comment-24473195-20161122164905

Unfortunately css doesn't allow such things. The easiest way to achieve what you want is to use the theme-source, e.g.: Template:infobox  Template:randomcol_infobox

Page content

Then create a css with "pi-theme-mythemewithoutimage" that will display when the image doesn't exist.

See also: http://portability.wikia.com/wiki/Thread:2361