Insert objects into array sequentially over multiple calls

I'm adding new photos to my database in groups as they are uploaded to Instagram. Say my first call to the Instagram API returns 5 photo objects in an array, [20,21,22,23,24]. 20 being the most recent and 24 the oldest. Then my next call several minutes later returns 5 newer photo objects, [15,16,17,18,19]. 15 being the most recent and 19 the "oldest" (but always newer than 20), and on and on.

Ideally I would like my database to store the objects as [15,16,17,18,19,20,21,22,23,24] or [24,23,22,21,20,19,18,17,16,15]. However, if I use push I end up with: [20,21,22,23,24,15,16,17,18,19], while if I use unshift I end up with: [19,18,17,16,15,24,23,22,21,20,]