Hello Lorena,
When you click on the various sizes of videos to play it also changes the embed code that you can copy and paste. The URL of the embedded iFrame changes slightly between the various sizes (Original, Large, Medium and Small)
e.g.:
original:
<iframe src='http://reels.creativecow.net/e/15474' width='900' height='506' frameborder='0'></iframe><p><a href='http://reels.creativecow.net/film/ccs-2010-kinetic-typography-open'>CCS 2010 kinetic typography open</a></p>
large:
<iframe src='http://reels.creativecow.net/el/15474' width='900' height='506' frameborder='0'></iframe><p><a href='http://reels.creativecow.net/film/ccs-2010-kinetic-typography-open'>CCS 2010 kinetic typography open</a></p>
medium:
<iframe src='http://reels.creativecow.net/em/15474' width='640' height='360' frameborder='0'></iframe><p><a href='http://reels.creativecow.net/film/ccs-2010-kinetic-typography-open'>CCS 2010 kinetic typography open</a></p>
small:
<iframe src='http://reels.creativecow.net/es/15474' width='320' height='180' frameborder='0'></iframe><p><a href='http://reels.creativecow.net/film/ccs-2010-kinetic-typography-open'>CCS 2010 kinetic typography open</a></p>
