Back in July, the Google+ Photos app for Google Chrome appeared in the Chrome Web Store, and was installable on the Mac but wouldn't work upon launching. At that time, it had been soft launched for the Chromebook Pixel about a month previously – though worked on other Chromebooks – and since then the listing has been disabled. However, if you managed to get it installed already, it appears to have magically begun working, and if you didn't get it installed there is still a way to try it out with a little Chrome trickery.
The Google+ Photos app is in simplest terms Google's version of iPhoto. Designed to be a front end to importing, uploading and sharing your photos to Google+, it's much more lightweight than something like iPhoto, but does what it sets out to do pretty well. I first noticed it had begun working when I inserted an SD card into my MacBook Pro, and the app auto launched in a separate Chrome window asking if I wanted to import the images from the card.
If you go to the Chrome Web Store right now, you'll see a message that states "This application is not supported on this computer. Installation has been disabled." Installing it is simple enough though, with a little trickery.
From there, restart Chrome, go back to the listing for the Google+ Photos app, and right click on the greyed out "Add to Chrome" button, heading down to "inspect element." The part you need to find is highlighted in the image above, and a quick cmd+F and a search for the text string is the quickest way. Double click on "webstore-button-disabled" and delete that portion. Hit enter, and the install button will turn green again.
After that, you'll have a fully functional Google+ Photos Chrome app, that launches in a separate window to the main browser. It'll still tell you it's unsupported, but click on "Run Anyway" and you're off and running. Importing, sharing, browsing, managing your Google photo albums, all right on your Mac.
In theory, the exact same situation should be applicable to Windows users as well, so if you're using a Windows machine and have this working, drop us a line in the comments. Is this something you could see yourself using?