1.Go to http://tinypic.com/
2.Click on choose file
3.Browse to the image you want to upload
4.Once selected the image click open.
5.Choose the appropriate size from the drop down menu.
6.Click on Upload now.
7.Then a captcha window will pop, fill in the text field from the image.
8.Then you will be redirected to a page with some links.Just copy the link under "Direct Link for Layouts"
9.Use the image tags on the post text box's gui
and paste the link or you can also paste the link between these tags manually