Hello,
How can i insert a jpeg picture as an email attachment so that when i
send the email with the pic, the recepient can click on the image and
go to the site i want him to?
Is there a free program that can do so, and if so, what's the quickest
way of doing so?
Thank you.

What email program are you trying to use?

For most you wil have the ability to either right click the image and
add the link or there will be a menu command in your toolbar.

Let everyone know the program you are using and you'll get a precise answer.

If your email clients support html then use this.

<a href="www.yahoo.com>
<img src="angry.gif" alt="Angry" />
</a>

Clicking on the image will redirect the user to yahoo.com. The image
can be in the  email itself or on different location.

HTML Images tags usage is explained here http://www.w3schools.com/tags/tag_img.asp

HTML hyperlinking is explained here http://www.w3schools.com/tags/tag_a.asp

HTH