Gather the images. Once you have decided on which images you like, put them together. Go ahead and cut around the paper if you have to. The whole idea is to see how this would look as a tattoo. If your image is not the right size, you could take it to your local copy shop and ask the person there to either reduce or enlarge it on a copy machine. This way you get a real good idea of how it would look and the size that you want. Trace the final image. No it's not cheating. Tattoo artists use tracing paper every day to sketch images for tattoos. Now you can do the same thing as you design your own tattoo. Lay out your images.
Tape them together if you have more than one. Put the tracing paper on top and trace the general image with a fine sharpie pen. Don't worry about getting it perfect, your tattoo artist will most likely do it over anyway. Take the originals. The most important thing here is to communicate clearly to your tattoo artist the tattoo design that you have in your head. You know, they say, "a picture is worth a thousand words".
So, take all of the pictures that you printed out, (even if they are the wrong size or color) and take your traced drawing with you to your tattoo shop. Discuss with your tattoo artist exactly what you are looking for as far as size, place, color, details, etc.. Your tattoo artist will take it from there. When people ask about your new tattoo, not only will you be proud to show it, but you will also be proud because you know how to design your own tattoo.