You'd never win that race.

Who said that you have to submit link to your server? Just force it to load large images from other servers. Well you can use help from Google search.

you'd flood your email server before you'd flood Google's cache.

But your email server would only need to send links to images that are gigabytes apiece, and that are generated procedurally, no?

The true bottleneck would be the pipe between your procedurally generated image server & Google's server.

Whose pipe is the one clogged completely by this? Yours or Google's? Congratulations, even if Google does this stupidly you just DOSed yourself. I'd imagine there are a ton of protections in place for their proxies to not take stuff offline, such as max-length limits, per-host limits, etc.