https://www.flickr.com/help/forum/en-us/72157646777274163/
https://itunes.apple.com/us/app/flickstackr-for-flickr/id364895358?mt=8
Haven't used it myself.
Good luck.
Cheers,
Scott.
bad_juju2 says:
Have you tried FlickStackr? I'm not sure if it will work on your iphone 4 but it will work on IOS 7. I'm not affiliated in any way with the app; I recently discovered it and like it a lot.
https://itunes.apple.com/us/app/flickstackr-for-flickr/id364895358?mt=8
Haven't used it myself.
Good luck.
Cheers,
Scott.