How browsers rasterize SVG in an image context
Loading an SVG through an <img> element (or drawing it to a canvas) puts the browser's SVG engine in a restricted mode: scripts inside the file never execute, event handlers are ignored, and external resources — fonts, stylesheets, referenced images — are not fetched. The document is rendered as a pure, self-contained picture. That restriction is exactly what makes a client-side converter like this one safe to use with any SVG you find: even a malicious file is only ever treated as pixels, never as code. It is also the source of the tool's main limitation — anything the SVG pulls in from outside itself simply will not appear.