gzip

GZIP compression is intended for text-based files and is not advisable for image formats that are already compressed. In the example of a .jpeg image, GZIP compression is below 1% in most cases. All browsers that support HTTP 1.1+ protocol include GZIP support as well.

https://www.maxcdn.com/blog/edge-settings/

text/plain, text/html, text/javascript, text/css, text/xml, application/javascript, application/x-javascript, application/xml, text/x-component, application/json, application/xhtml+xml, application/rss+xml, application/atom+xml, app/vnd.ms-fontobject, image/svg+xml, application/x-font-ttf, font/opentype, application/octet-stream