Q:

Event Bus and large data best practices

I'm in the process of using an Event Bus, for all the various benefits. 
I know that an Event Bus is just for passing small massage, as this is its core usage. 
Are there any design patterns or architectural patterns for the Event Bus handling large data items, like images or videos? 

A:

The architectural pattern is called Claim Check pattern. 
Microsoft has documented this pattern with various options for implementation in Azure (document).  The general pattern description is available here.