I feel your pain brother. I had a hell of a time at first. Now, I am a picture posting whore.
I also use imageshack. Here is how I do it and it is probably the slow way(some help for me here too, please). When I am at the page with all of my photos, I right click on the one I want. Then click on "view image". When that opens up look at the bottom of the picture and you will see a magnifying glass. That is zoom, click on it. Then it will open another page with just the photo. Copy what is in the browser at the top of the page. Then go to the thread you want to place the picture in. There is a little picture of a mountain to click on to insert image. Click that and paste the link you just copied. Be sure and remove the "http://" that is already there or it will screw you up. Damn, sorry about all this, good luck. Told you, I need help too.