Automattic
ImageDownloadService: Investigate other caching behaviors
Gravatar supports some cache control headers. Let's investigate and experiment on different cache policies that are defined in Apple's high level networking frameworks and see how we can offer other caching behaviors.
I'd also suggest creating a custom URLCache instance so that the framework doesn't store images in the default system cache that has a very limited capacity on iOS.
We have investigated this. And it turns out that Gravatar backend doesn't support cache control headers, they are ignored even if we send them. We need to address this at the backend so I'll close this issue as part of a backlog cleanup.
Creating a custom URLCache instance could be helpful for the capacity so we'll evaluate how this fits into our roadmap.