Inserting svg files in properties marked with UI hunt "Image" makes an nullref error in the logs, and the image looks broken to the editor. Ref: https://support.episerver.com/hc/en-us/requests/291373
SVG files are sometimes the preferred format when displaying logos and such, so this should be supported. It's easy to get thumbnails in the asset pane to show up for SVGs, but the image property itself lacks this support.