I believe you have to post the URL into the signature line. That means that the pic has to be posted onto a website rather than your laptop. I like photobucket, it's free. After you register with photobucket and upload pics, you just click below the pic on the address of the "direct link" (http:/ whatever...). Then use that code in your sig line by cut/paste...

Pictures will post on a thread using the file uploader (which you have found). You must resize the pic to be small enough to upload here. Depending on what you use to do that (I use photoshop) the instructions will be different. There is an "image size" and a "canvas size" that you can change using the toolbar functions under "image". Try playing around with that and see what works using the "test board" page on this site. This can take a while and be confusing but you'll soon be able to everything you want... and more.

Good luck. PM me if you need more help...