(Applies to: FusionBB version 2.0 and newer)
When you add the image files, in the popup where you add them, you'll see a preview of the image. There's an icon next to the preview (in the popup) which when you click it, will transfer the appropriate url code into your post. Then position it where you wish.
When your post is uploaded (after you click the Finished button), your image should be where you placed your cursor. Note that the file(s) will be listed at the bottom of the post.
Using the [float] code tags will allow you to place the image to the left or right and will allow the text to wrap around the image. You will have to input these tags in by hand, such as:
[float:right] (Image file code) [/float] or [float:left] (Image file code) [/float]
(Please note: there is no [float:center]-- if no [float] tag used, the image will be placed in the section you choose to place it at and will be in the center, by default.
If you do not use the icon in the file upload preview to place your image, it will default to the top of the post.