Google Lens seems not to support SVG on its GET endpoint. Trying with one results in a "Something went wrong" page even though the GET returns a 302 with a valid redirect URL, just like successful requests. I don't know what other common formats might be unsupported.

We should probably just hardcode a check for SVG and not show the menu item. Long term we might want the ability to specify supported image types for visual search URLs in the search config, as a way of generalizing it.

Alternatively we could convert unsupported types to jpeg on the client and then use the POST endpoint, but that's out of scope right now.

Example pages with embedded SVG:

• https://searchfox.org/mozilla-central/source/browser/branding/official/content/about-logo.svg
• https://www.svgrepo.com/svg/4733/samples

Wikipedia and other Wikimedia sites seem to use PNG previews for "embedded" SVGs.

This is built on this PR.

Depends on D259887

https://hg.mozilla.org/mozilla-central/rev/310e29c2be8a