The way I was taught and what works for me:
Go to photobucket.com or any photo hosting site. It's free. You sign up with a username and password. Then it'll give you an account where you upload your pictures to. Takes very little time.
Once picture is uploaded, you get options. Hover your pointer on the thumbnail of your pic and choose "direct link". Copy that code in your browser by holding Ctrl c on your keyboard.
Then paste that code into your posting here. You can then preview to see if it worked. I fretted and cussed a long time before I got what was supposed to be so simple to work, but this is the method I've seen suggested on several other forums. I'm finally getting the hang of it.
If you have probs, post again n tell me what happened and maybe I can help.
Seems roundabout, I know but it works.