Different Types of Packets

I'm using a sniffer and I would like to know is there a way to tell a download packet fro开发者_JAVA技巧m a packet that comes up when you go to a website? Are the headers different? If so, what is the difference? Is the size different? Any clarification is appreciated.

It's not 100% clear what you mean, but the browser will use the Content-Type and Content-Disposition headers to decide whether to display a resource in the browser or to show the Download prompt. Is that what you meant?