cookiescookies - first welcome to CC, you will soon become addicted like the rest of us
Here is how I do my edible image cookies. I use MMF as my base, it has a couple of advantages. I think it is easier and quicker to apply and you do not have to wait for it to dry.
After the mmf is applied to the cookie, I use thinned corn syrup to adhere the edible image, take a small brush, estimate the size of the ei to the cookie and apply a small amount of the corn syrup in a smaller size area on the cookie. What you are trying to achieve is slightly sticky area on the cookie that the edible image will cover. Place your ie on the cookie, gently move it a little, so the corn syrup gets to the edges, then smooth with your finger. I then take an embosser and go around the edges, try not to get into the ei with your embosser.
I do mostly circle cookies with the ei, but I have done hearts. To make my edible images perfectly round, I use a punch that is dedicated to cookies. I print my edible images, make the cookie about 1/4 in bigger all around than the image, that gives me room to do the embossing. I take the sheet of icing images and cut a row of them off the main sheet. I then take the actual icing sheet off the backing and cut the ie with the punch. If I am going to use them right away, I don't bother to cut the backing, if I am going to store them, I punch a circle out of the backing and layer them back together. You could do the same thing with the heart.
Here is a link to a heart punch:
Here is a pic of some Christmas cookies I did this way.
Sorry this is so long, hope this helps, if you have any questions, please pm me