[Berserker]

I see that many of you post pics of your personal guns. How do you do this without attaching a file from your PC?

 

[Flyer]

To attach pics that way, they've got to be stored on the web somewhere that you can link from directly into the post.
A lot of us have our own websites with space for storage, and there are sites available with free storage.
Some of these free sites don't allow you to remote link pics, though...
Anyhow, if you see a pic in someone's sig line, like my AR firing guy below, he's linked to from my personal website.
Flyer

 

[Midiman]

Just be sure to include the complete url that points to your graphic... http://www.whatever and surround the URL with image tags:

and please be sure the graphics you link to are not in excess of 640 pixels in width...

 

[Jeff Johnson]

I see that many of you post pics of your personal guns. How do you do this without attaching a file from your PC?

I use photobucket.com, which is free, for hosting photos that I want to post elsewhere. Easy to use.