Are “source” fields for image array persistent, or do they change?

Question

Does anyone know if the source field in the images array for photos is persistent? Seems like it's a dynamic pointed into the FB CDN - we're trying to figure out if it's safe to cache those links in our DB, or if the photo should always be re-queried before we load it? Do they change over time? Locale?

"images": [
            {
               "height": 1152,
               "width": 2048,
               "source": "http://sphotos-d.ak.fbcdn.net/hphotos-ak-ash4/s2048x2048/394054_352972968053308_1128645961_n.jpg"
            },

Answer 1

Yes.. this is a CDN hosted image. The URL is likely to change depending on server load and the users location. I don't recommend caching those URL's.