"Check via URL" option (available for premium users) will add photos to our database. This works only for photos with public URLs (local files are never uploaded to the site).
This works similar to Google Image Search or Pinterest.
While we try our best to link to sources/author's website, the process is automated (based on Google Image Search API) and doesn't always produce correct results.
If you'd like to remove your photos from this site, contact me.