This is a good method...but a less involved one (for those of us less experienced) would be to use this tutorial.
Do not plug in the YouTube embed code as YT(YouTube) gives it (you can try, but it will be ganky)...instead just replace the source from the embed code of your vid UP TO &autoplay=1
(leave this on the end as it is).
eg.
original code YT gives:
<object width="420" height="315">
<param name="movie" value="//www.youtube.com/v/5mEymdGuEJk?hl=en_US&version=3"></param>
<param name="allowFullScreen" value="true"></param>
<param name="allowscriptaccess" value="always"></param>
<embed src="//www.youtube.com/v/5mEymdGuEJkhl=en_US&version=3" type="application/x-shockwave-flash" width="420" height="315" allowscriptaccess="always" allowfullscreen="true"></embed>
</object>
Code used in tutorial with same YT src:
<object width="420" height="315" classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,40,0">
<param name="allowFullScreen" value="true" />
<param name="allowscriptaccess"value="always" />
<param name="src" value="http://www.youtube.com/v/5mEymdGuEJk?version=3&hl=en_US&autoplay=1" /><param name="allowfullscreen" value="true" />
<embed width="420" height="315" type="application/x-shockwave-flash" src="http://www.youtube.com/v/5mEymdGuEJk?version=3&hl=en_US&autoplay=1" allowFullScreen="true" allowscriptaccess="always" allowfullscreen="true" />
</object>
Other than that, just replace the img source and path with your own, and voilà!