Or................. you can press the "Go advanced" button in the bottom of the quick reply screen and then click "Manage Attachments" , the button way below the advanced box's text area. A box will pop up, use a BROWSE button, that is, press one of them and go find the picture you want. Click it and then click then click the "OPEN" button. The window closes and you are back to the browsing box. Click UPLOAD (a lot of people miss that step).

The picture should be there. But it's just a thumnail! Ya gotta click it to get the full sized image.
And you DO want to see it, dont' you?