There are easier ways to insert a picture into your posts.
When you click to reply or start a new thread, most of you will see several icons across the top of the text box called a toolbar. The 5th from the right (a square icon) is the tool for inserting a picture. Just locate your cursor, then click the icon, and enter the url (web address) of the picture.
If you do not see a toolbar across the top of the text box, you can reset your preferences to add the toolbar. Go to your Control Panel (click User CP in the top black banner), and click Edit Options in the left column. Then scroll down to the bottom of that page to reset your Message Editor Interface.
We can also reset this for anyone who wants us to.