Google's old desktop app "Picasa" is still my go-to for organizing photos. I make a file system folder for each "album". Everything stays local on the fs and there is no doubt about where the originals are (compared to iPhoto/Photos.app, etc etc). OSX' built-in Time Machine to an USB drive + rsync to a NAS takes care of multiple backups. I can easily drag&drop files into apps and upload forms with no doubt that I'm working on the best possible copy (original).
Too bad the app appears to have been going unmaintained for some time now. It doesn't even support retina displays on OSX (in a photo app!)
Me too! I don't like it when programs insist on storing my photos in their own, non-human-readable directory structures and file names. Otherwise it becomes a nightmare trying to use them in other programs. Even iPhoto->Photos managed to break my library.
I just wish that Google would bring back the simple online photo sharing that they used to have with Picasa. The Google+ merge ruined all that.
If you're willing to keep your photos in Dropbox and have the space for it, take a look at Carousel.
Carousel respects whatever folder naming convention you have. All photos in your dropbox show up in Carousel's photo list.
Pictures on Carousel are always saved to the "Carousel" folder in your dropbox, but you can move them around to respect your preferred folder structure without damaging anything.
Not sure. My intuition is that photos are completely read-only; I don't think it will ever change them, so tags might be stored in some other opaque storage.
I do know that Carousel uses the DateTimeOriginal EXIF tag to set the date. You can use this command to re-tag photos, for example:
Piacasa is the best, both native and the online version. I still use it but its a bit confusing now that it some how has the Google plusiness added to it online
On Windows the good old "Windows Live Photo Gallery" program that come with Vista (and is available for Win 7+ as download), is still a good alternative. The good thing it doesn't force one to use a database based album system. The photo files stay were the are, it only reads/extracts the metadata and optionally the user tags can be embedded back to the original file.
Too bad the app appears to have been going unmaintained for some time now. It doesn't even support retina displays on OSX (in a photo app!)