You need to store the picture in "the cloud"; i.e., any of the free (or those that charge if you so desire) storage repositories on the web for photos. I use Photobucket, others use Flickr, etc. The cloud service that use, you'll need to set the permissions to "public" in order for the url to actuallly display when someone opens the thread and you need to leave that image's url information alone. If you change anything in the image tag (the url's information); i.e., the name of the image or the location on the service's server, etc. the picture will disappear from the thread.
Once you have your pictures in the cloud, you can use that image's direct url in the "[img]url[/img]" tag sequence.
The picture of my old FunFinder, with the image in Photobucket would look like this (substituting a [ for { and a ] for }):
{img]http://www.funfinderclub.com/attachments/photobucket/img_5702_1_8b872e50f70cd42e17292f601a29b000.jpg[/img}
The above with the { and } changed to [ and ] makes the picture below show up:
To make things easier on everyone; the moderators, the web hosting service and the software this forum works on, photographs should be resized to around 500 pixels in width, 620 max, so that server space is conserved, scrolling is avoided and everyone can see them. The above picture is 500 pixels wide. Larger can sometimes work, but, not all services are capable of displaying larger (when software burps on larger images you get the "red X in a box" problem and others will blow the page up causing the user to have to scroll left and right to see everything. 500 pixels will show in just about all browsers, has adequate detail and is useable in just about all forums so the images you store in "the cloud" are useable for multiple platforms, forums and packages.
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