Combine photos from multiple people's iPhones into a single location?

My wife and I have different iCloud accounts. We would like to have the photos from all our iPhones (I have 2) to be combined in a single location. Is there any way to do this? I had thought we could use the Google or Dropbox uploaders, but it seems that they don't run in the background.

We've tried family sharing and have had issues with it. Specifically, we don't reliably see photos from all devices, we don't get images from our digital cameras unless we import them into a Mac, and it's not clear how to export all of the family sharing photos to an archive.

Use Google Photos. This being a fairly new app, it did not exist at the time this question was asked.

Google photos is a new (free!) service that allows you to upload all your photos to Google Drive, automatically. You can also share all your photos with anybody you want, using the new Share Your Library feature.

You can download the app from the App Store, or access them on your computer. There's also a desktop uploader in case you want to upload photos on your computer automatically.

The best part about this app is that it allows you to delete all the photos you uploaded from your phone, freeing up storage space on your phone. Your photos will still be available through the Google Photos app.