If all I want to do is use a picture to illustrate something in one of these posts, let's say an example of a part for illustration purposes. I just find an image on on the web and right click on it to see the "properties" of the image which includes the location url for that particular image. I copy the complete url and then in my posting, I insert the url between these two commands
That will put the image right there:
If I have an image of my own (i.e. photo) that I'd like to use in my post, I upload it to tinypic.com. That site will then give you an url to point to that image:
http://tinypic.com/r/2hia3p0/3
and will also give you a cut and paste image command (like the one above) to actually insert it: