Go to the location where the picture is stored with your browser and view the picture. Right click on the browser search bar and select copy. Go to your post and right click and select paste. The system will make the address from your browser into a link.
Since you are a club FTE member if you have a picture on your computer that is small enuf and the right type use the advanced post system and select "Attach files" on the lower section of the page. Follow the directions to browse your computer for the file and upload it.
Check some of the other posts in this forum. Many others have asked this question!
As far as moving pictures on your computer there are books at the local bookstore that will help with manipulating your computer.