When testing 288094: Allow brackets in createImgThumbnail, I discovered that if SVG isn't supported by the UA, then the thumbnail is requested but isn't rendered:
This is because the styles that position the SVG thumbnail aren't applied to the <div> fallback created by #createImgThumbnail (see resource/ext.popups.core.less).
Browser: Google Chrome (50.0.2661.94)
OS: Mac OS X (10.11.4)
