The first is to scroll down while writing your post and click on the "Manage Attachments" button and then click on "Browse" to find the file on your hard drive. Then click the upload button. This will put a thumbnail (small version) of your layout at the bottom of your message that can be clicked on that will open the larger version.
The second method is to find a layout in your gallery. Underneath your layout in the gallery you will see an item called "UBBCode:". Copy the whole line there that starts with "[img]" and paste that into your message to display a large version of your layout in the message.
Hope this helps.
If I slip and fall please get a hold of crops2dawn or OnieRN to pick me back up!