I switched to Lyn (http://www.lynapp.com) from Picasa a few years ago and never looked back. I liked the more native interface and the same ability to work directly with files and folders instead of a database like iPhoto or Photos.app.
It seems that your comment contains 1 or more links that are hard to tap for mobile users. I will extend those so they're easier for our sausage fingers to click!
Here is link number 1 - Previous text "Lyn"
^Please ^PM ^/u/eganwall ^with ^issues ^or ^feedback! ^| ^Delete
Others have given good answers about Lightroom. I was dealing with this earlier and, for me, Lightroom (2.0) has been buggy and slow of late. I picked up Lyn which does many things but in part lets me quickly separate the good from the bad (I have LOTS of bad). I then import the few good ones into Lightroom.
I also shoot RAW+jpg so I sort the jpgs (faster) and then run that to delete the corresponding RAW files. It's a convoluted setup but it works for me as a noob.
You can't just put the Photos library into your DropBox directory? The only thing offhand that I can think of that is similar to photos is Google's Picasa, but that's getting a bit long in the tooth with no updates.
http://www.lynapp.com looks decent, but again I think it's been a while without an update
http://www.pixa-app.com also looks pretty good
Those are what I've seen!
Edit: I just tried Pixa and it's pretty decent. * Multi-tab interface * Fast import * Imported my Photos tags properly * Imported GPS data (but no apparent way to view it on a map or change it) * Live folders * Supports uploading directly to DropBox, CloudApp (whatever that is), and Imgur (seems to do that by default, no setup required)
Biggest thing is that it lacks photo editing ability. It's strictly an organizer. But if you are editing your photos elsewhere, seems like a solid choice.
I'm not sure what you mean about the drag and drop. This app (http://www.lynapp.com/) I think may be good for you. I haven't bought it yet, but intend to. I've been using for a while to view folders of images, either recursively or the single folder. I can drop a single image on the app and view the entire folder of images.
The other app that I used to use is XNView. Its free.
I think you are referring to this post: Mac equivalent to IrfanView?
And the 2 applications that look the most like what you describe would be:
- Lyn
Hope this help!
For browsing photos, this app is a pretty good lightweight app: http://www.lynapp.com
It doesn't detect duplicates, but there are a variety of duplicate detection apps like Gemini on the app store.
There's another recent new one too that's like Lyn, but the name escapes me.