It should look like this when you're done:
click here or on picture for big version
Here's the directions-- they're more complicated to read than actually doing it:
First, get two versions of your picture online-- one small one suitable for embedding into a post (less than 500 pixels, please), and the original big, huge one.
Then you need to post the small image as a link to the big one.
The easy way for a PC user is to open the big version of your picture in a browser from the website its on (make sure it's not a link already by clicking on it until nothing happens), then right-click on it, and select "Copy Link Location" (FireFox users) or "Copy Shortcut" (IE users).
Then click the http:// button in the post editor.
Paste in the picture location that you copied when it asks for a URL. You can leave the title alone or make it "click here to see my big'uns" or whatever.
You'll get a string of code in your post that looks like so:
[URL=http://www.shred2.net/~shred/gallery/ColumbusCup/IMG_1810.jpg]click here for big version[/URL]
Now go copy the internet location of the smaller image like you did the big one.
Press the IMG button this time and paste in that location when it asks for the image location. You'll get another line of code looking like
Now do a cut-and-paste of everything from [IMG ] to [ /IMG], including those [IMG ] tags and their brackets and stick it either next to or in place of what you wrote for the web page title, so your your code looks like this (make sure it gets in after the ] and before the [ /URL]):
[URL=http://www.shred2.net/~shred/gallery/ColumbusCup/IMG_1810.jpg]click here for big version [IMG]http://www.shred2.net/albums/ColumbusCup/IMG_1810.thumb.jpg[/IMG][/URL]
Hit Preview Post and see if it looks OK, but don't click the picture, or you may lose the post you were working on. So long as it looks ok, post it, then check it. If it didn't work, go back and try again.
If for some reason the link shortcuts you got don't end in .jpg or .gif or another picture format (the board will complain), you may need to right-click the images you want and select Properties, then manually copy the image location instead of using the Copy Shortcut or Copy Location commands.