Ask HN: mobile data transport SDK?

Hi there hackers,

We want to find a way to post multiple photos to a server as a background process in our iOS and Android apps.

While we can certainly build this ourselves and post to S3, I wanted to know if you have any recommendations for an SDK or library that handles this well. In particular, there are issues such as handling different photo resolutions and dealing with wireless connection interruptions (e.g. suspend/resume).

I know of Parse and Kii... are there other services that you might recommend?