Use Google search as normal, enter your search words and start the search. Once the results have loaded choose Images and a camera icon appears in the search bar:

Clicking on the camera allows you to upload a photo or give a URL with the photo you are trying to identify. Once loaded scroll down a bit and click on 'Visually similar images'.

If you are lucky you may be able to scroll through those and find what you want. I say 'if you are lucky' as it is far from perfect and has only worked occasionally for me. Also not all images are named.
I was trying to identify this moth I spotted on Sunday:


As luck would have it there was one shown which looked very similar so I think there is a good possibility this is a Poplar Grey moth (Subacronicta megacephala)
Not my month for getting identification correct. Many thanks to Ragged Robin of Ragged Robin's Nature Notes for pointing out this is an Early Grey not a Poplar Grey Moth.