While this would be interesting as a matter of engineering curiosity, Everpix's AWS bill was not close to the #1 hurdle between them and profitability. It seems like low hanging fruit, but you'd be optimizing away something small relative to, say, their employee costs or per user revenue.
Seriously, they should have went with dedicated boxes on something like Softlayer comme Dropbox. Unlike CPU-cycles, storage needs are relatively predictable as people usually don't remove photos after uploading them.
Softlayer - yikes! Was with them once and never again. AWS is far more flexible and cheaper (based on my experience). Not to mention the full suite of services available under the 1 umbrella from AWS where Softlater just cannot compete.
Good question. I've seen a lot of people claiming AWS was the wrong choice from the start, but IMO at the stage Everpix was at, the flexibility of AWS would still have been a reasonable and viable choice.
But $35k for only 55k users just doesn't add up in the absolute sense, AWS or not.