Add Location to Photos I know this is possible with third party applications, but is it not possible to add location to an image using the standard Google Photos app, either from the website or mobile app ? Just realized I had the location turned off on my Camera app after a trip, and would like to be able to search the pictures by location.

I have seen this question which suggests there is a way, although I believe this is an older version as I cant find that option anywhere.
I'm afraid it's not possible using the standard google photos app, you would need to use some photo-processing software to set locations for photos after they were taken (Picasa comes to mind). Alternatively, you can use the G+ page https://plus.google.com/photos/yourphotos to edit the GPS information, but then again i'm afraid you can only do this one by one. Maybe it's best to just turn on the location feature while taking the photos and you're done