Okay...I just figured this out tonight. If you currently have a photobucket account you can add links to the posts, but then people have to click them to view 'em. Instead I suggest clicking on FILE MANAGER under where you have typed your post. It has a browse button you click and find the photo on your computer hard drive. Then click ADD FILE or ADD PHOTO (can't remember the terminology they use) When you are finished click on Done adding Photos at the bottom of that box. If you click preview on your message - nothing happens, but once you hit submit you will see your photo added to your post. I hope that helps. It took me forever too. lol
Donna did a pretty accurate job of describing how to add photos using <span style="color: #000099">File Manager.</span>
To determine the size of your pictures, right click your picture, then click properties. That'll give you info about size, etc. To resize, you can use your photo editing software if you have it, or use the Paint program that comes with Windows.