So I did get a reply. I won't bore you with all the details, but the gist is that they're finding running all these cloud servers to be expensive, the user base is expanding, and the implication is that revenue from the camera sales isn't paying for the server costs. So somehow the ads are going to help with this, the implication being that maybe we'll start seeing ads for other stuff (like most ad-based apps?).
He did promise to forward my concerns to management (hopefully unedited, so the message is crystal clear).
I plan to reply that they'd probably get a lot less push back if the ad was less intrusive, and less often (once per session rather than per file?).
For all others irritated by this, recommend you also send a note to
cs@pittasoft.com. Be polite, but clear.