Hmm, looks like the Chrome Android screenshot didn't upload for some reason. Another try...

Google sends a different website to Firefox. It is up to Google to give Firefox a better experience. You can provide feedback to Google at https://productforums.google.com/forum/#!forum/websearch

That's curious, since the Windows version of Firefox does indeed display the complete google.com toolbar that contains this button.

I do realize that Google is naturally tooth and nail against using any browser but Chrome, but it makes no sense that they would restrict this function on Firefox Android only. I would certainly think that if it was intentionally done by Google, it would be hidden in all versions of Firefox.

Also, Firefox Android has what seems to be all of the other google.com toolbar functions via its "More" and "Even More" pull-down menus, although I haven't checked them one-for-one. The only thing that seems to be missing is that "Search Tools" option.

This is a real showstopper in my opinion, because basic sorting and filters are a must in a web browser. Sadly, regardless of the cause, I guess it's time to switch back to Chrome across the OS board since those functions are available in all versions.

This is not a new problem, so I suspect that complaining to Google will not help. Here's a thread from 15 16 months ago: I can't find search tools on google with the android Firefox. That hack still "works" -- the reason I say "works" instead of works is the image results page is glitchy when Google serves Firefox the page designed for Chrome.

Great, ticking the "Request desktop site" box works! The "images" link displays the results fine on my device.

Hard on the eyes, but turning the phone sideways helps with that a bit. I don't know why I didn't think of trying it earlier.

Thank you for the suggestion!