You probably do know what a URL is, but just don't know that you know.
A URL is a web address, such as http://antwrp.gsfc.nasa.gov/apod/image/0406/.
The first part of the URL, http://antwrp.gsfc.nasa.gov, is called the domain name.
To post a picture just get the URL of the picture itself, such as http://antwrp.gsfc.nasa.gov/apod/image/0406/q4m44_westlake_big.jpg (q4m44_westlake_big.jpg is the name of the picture), click "Image" on the JoeUser toolbar, paste it into the "Script Prompt" box and click OK.
Note: URLs for pictures always end with picture extensions, such as ".jpg" or ".gif".
To post a picture already available on the Internet, such as http://antwrp.gsfc.nasa.gov/apod/image/0406/q4m44_westlake_big.jpg, you first have to find the URL. There are two ways to do this.
If the picture doesn't link to anything (that is, clicking on it doesn't take you to another webpage), then you can click on the picture, it will appear alone in your browser window and then you can copy the URL out of the "Address" bar in you browser.
If the picture in question DOES link to another page then you CANNOT just click on the picture. The easiest way to get the URL will be to click "View", then select "Source" in your browser's main toolbar (i.e. "File", "Edit, "VIEW", "Favorites" etc.). A notepad window -- with all the code for the webpage you are viewing -- will appear.
Don't worry, just search for ".jpg" or ".gif" until you find the a picture with the appropriate name. You can search in Notepad by clicking "Edit", then selecting "Find".
Copy the URL. If the URL begins with use a "/" or a "../" you'll have to add the domain name. That is, "/apod/image/0406/q4m44_westlake_big.jpg" becomes "http://antwrp.gsfc.nasa.gov/apod/image/0406/q4m44_westlake_big.jpg", or "../apod/image/0406/q4m44_westlake_big.jpg" becomes "http://antwrp.gsfc.nasa.gov/apod/image/0406/q4m44_westlake_big.jpg".
Once you have the URL just follow the instructions above, click "Image" on the JoeUser toolbar, paste it into the "Script Prompt" box and click OK.
If you want to post pictures of your own, you'll have to have a "hosting" service to store them. A hosting service provide you with space on a server, connected to the Internet, so that when people load your blog the picture will also be downloaded from the service's server.
You save the picture to their server, then copy the URL where it is stored into JoeUser.
Hope this isn't to complicated, just start off easy with the first picture you find.
