I've been working on reworking to the backgrounds selector in System Settings, based on these designs. It isn't quite complete yet, but getting close
None of this is merged in trunk yet, but should be real soon. Here's a glimpse of what's coming.
With different backgrounds for welcome and home screens:
With the same backgrounds for welcome and home screens:
Browsing available backgrounds:
Current background is indicated by the orange border.
Notice the Photo/Image button on the toolbar above, that opens gallery-app to select photos from your personal collection.
Photos that have been used from the gallery will appear in the Custom section of the grid:
Selecting a background, either from Ubuntu Art or from your gallery, brings you to a preview to let you confirm your selection:
If you read the design spec, you'll notice this isn't completely to design yet. I still need to implement a resize/crop tool for photos you select from your gallery.