As the title says. It'd be nice to have oneboxing optional on mobile chat, especially if it were something like click/tap-to-reveal.
Why? Well... my data plan is crying at the tens-of-MB GIFs that get posted now and then.
Add support for .gifv format in chat onebox
One of the recent(-ish) changes imgur made is allowing far larger GIFs now. 200 MB is the current limit.
Overrides/preferences for chat oneboxing
Very closely related, but I feel this is far more significant for mobile users with low data limits, and therefore worthy of a separate feature request. It doesn't even have to be a preference - oneboxing could just be disabled entirely on the mobile site (though of course I'd prefer the option).
This has security implications because an attacker can post an image of arbitrary size on any server with sufficient storage and bandwidth and link to it on chat. Because chat automatically loads direct image links from any source, one could, with relative ease, post multi-GB animated GIFs and quickly exhaust user data allowances, effectively denying service to chat users.