Different people do them different ways. I print my images using the best quality photo paper because I have found that the cheaper paper causes the image to bleed when I apply my resin.
I buy flattened bottle caps. I boil the caps to loosen the seal on the inside and remove the seals.
I use a nail and hammer to make my holes in my caps.
I glue the image to my bottle cap using a regular glue stick.
I don't seal my image with anything before I apply the resin.
I use ET Lite applied to the top of the image. As long as I use premium photo paper, I don't have any problem with the image bleeding.
After drying, I add a split ring (the ones that look like small key chain rings) to the cap and hang it on a necklace.
Some people don't flatten their caps and have diffent tools that they use to create their caps, this is just the way I do it