Hi Thomas,

You have set an image to be placed on the time-line - it's 6 seconds long, place another besides it making two images totalling 12 seconds. Now add a Fade transition of two seconds. The Fade and every other transition merges the two images so they over lap each other. In this instance the Fade default length of two seconds means half of the fade's time of one second will come from one image and the second half of the fade from the other. The fade makes the images over lap by one second. If you set the fade to one second then half a second from each would be the merge.

You will end up with a shorter display BUT you can control both the length of the images and the length of the fade by changing the default settings and you can alter them individually with a double click on them in the time-line... also using the cursor extend option control (click and slide the edge).

Edit > Preferences

One additional note about transitions: A transition can be no longer than half the legth of the shortest clip.

Dafydd