Making the iris textures is actually pretty simple. Start out with a pic of an iris. Look around on the net for examples. You should be able to find some that are for free use. You can also start with a scanned image of an iris you photographed. Use an image modifier tool in your paint program of choice to contract the pupil as small as possible. Switch the image to black and white then back to 24 bit color or use a de-saturate tool. All you want here is a gray version of the iris to use in the next step. Put a circular mask as a layer around the iris and flood fill it with a circular two color fill. Set the transparency of the fill so you can see the gray iris image through the fill. That's it! As to using the textures for your images, I don't have a problem with that at all. All I'd ask if you do publish them in an image is to include a credit.