Bandwidth shouldn't be an issue here, although this is a side project (so I realise money is limited), from experience you can send and receive roughly 200-400 images per second for every $5/month you spend. I don't know your precise usage count, but I would be surprised if you were to get that many images downloaded every second.
I probably don't have the bandwidth to support a full-blown API, but making a web app that makes bulk creation faster is a priority.