After you add a picture to your message you can resize it before you hit send. After you have uploaded a picture to a post, click on it. There will be little white square boxes around the picture. Move your cursor over to one on the sides ( you will see little arrows , click and hold and drag ) and move in. Then move your cursor to one on the center bottom of front and adjust up or down to make the pic smaller. When the pic looks like the original, but in a smaller version then you click outside the picture and the little boxes will dissappear .... you have a smaller version of the large one and not so much space.