It's pretty easy.
step 1:
upload an image on some image hosting site. like photobucket or something.
step 2:
Once the image uploaded you'll receive a link. Copy that link.
(it should be something like this: http://i284.photobucket.com/albums/ll6/tsuto_tsuto/minimap.jpg
-I'm using tsuto's link)
Step 3: [
Add the [img][/img] tags before and after the link.
So you should have something like this:[
[img]http://i284.photobucket.com/albums/ll6/tsuto_tsuto/minimap.jpg[/img]
Notice how the tags are written without any spaces? Do it like that and it should work. Of course use a link to your own image.
If you did everything correctly you should see something like this:]
[img]http://icanhascheezburger.files.wordpress.com/2007/10/lolcats-funny-pictures-submissions.jpg[/img]

But please, remember to use moderately sized sigs, and avoid anything that could cause controversy. Otherwise you'll have to face the wrath of moderator kitteh!

lol...im that cat ritee there....>_>

As if handcuffed, I'm bound to the memories of you...

Quote from sweet despair

lol...im that cat ritee there....>_>

You poor thing. They must be crazy if they don't like your submissions.

This signature was recovered from Hades to serve in my rotting armies.

Quote from x0mbiec0rp

Quote from sweet despair

lol...im that cat ritee there....>_>

You poor thing. They must be crazy if they don't like your submissions.

technology just hates me T^T

As if handcuffed, I'm bound to the memories of you...

You need to link an actual image file (like with a .jpg or .png extension). Linking to a folder or directory won't work

A just ruler amongst tyrants

ok you got it perfect except for the spaces, remove the spaces and your image will be there.