Hey potts please don't be offended. I'm just trying to help. I'm wondering if you are having trouble with the concept of it or just the navigation on your computer.
I can help with either.
First the concept:
You start with a picture that is already on your computer. Lets assume you put the picture in a directory (also known as a folder) called Pictures.
You need to upload any pictures you want to share to a server on the internet. There are several to choose from. ImageShack or PhotoBucket make it fairly simple.
On their web page once you are logged in you click on a button that usually says something like "upload picture" or maybe "browse". When you click that button the web server pops up a window that is essentially asking you where the picture you want to share is located. Assuming you have them in a folder called "Pictures" you would browse to that folder using that pop up window and selecting the picture you want to share.
Once the photo is uploaded to to an internet server you copy the link to it's location on that server into the forum by clicking the add picture icon at the top of the message window.
As far as navigation goes there is a way you can let someone you trust see and control your desktop using special software. We use software like this at work to help clients with problems.
If you were interested in something like that let me know. I could remote into your computer and guide you through the whole thing from here.