Some will allow hotlinking and others might require actually saving the .gif and uploading it to a picture host, like ImageShack. http://imageshack.us/
On here, like most forums, you use the same format as displaying a picture. Copy the address for the image, click the Img button above, paste the address, then hit the Img button again to close the “tags”.
If you look at the Deep House Smilies page, you’ll see how they should look on here before posting. The Deep House one already has the Img tags on each end, so just copy and paste the whole thing to here and that’s it! To copy and paste, click and hold down the Left mouse button and drag the mouse across the address (URL), then Right click on it while it’s highlighted and select Copy. Come over here and put the mouse in the typing area and Right click the mouse again to select Paste. You can also use keyboard shortcuts, but you still need the mouse to drag over the address for the image.