No problem.
I used to be computer illiterate...well, I still am, but you understand.
There's one of two ways. The first is to attach the image to your post, by clicking the 'attach file' button when you're posting something. But most images I find to be 'over the size limit', so I don't use it.
The alternative (better) solution would be to create an account at
http://www.photobucket.com. You can upload images from the internet or your computer there. Just hit 'browse' on the 'upload from computer' part and select the file you want to upload. It'll be added to your portfolio. Then, copy/paste the URL (link) or the link in IMG, here, and it'll show up. (In 'IMG', it'll show up as an image, whereas otherwise it'll just be a link we click on to your image).
Hope that helps you.
Edit:...