Working on this right now and thought it might be helpful to explain how I'm tackling it. For the rules PDF, I'm using the PDF Optimizer feature in Adobe Acrobat Professional, though it didn't have much of an impact this time around because the rules PDF was already quite small.
I downloaded your tile images and I see that they are in JPG format. This is a pain in the backside for printing purposes because it might come out at the wrong size. It is best to convert the JPG to PDF, and the easiest way to do that AND make sure it will print the correct size is to import the tile images into Microsoft Word and create a PDF from there. Microsoft Word has the ability to size images to specific print sizes.
Ideally, all the tile images should be imported into Microsoft Word separately. You've got several tile images in one image, with white space in between. Although the white space appears to be "empty", it still contributes towards the overall size of the image; fortunately not as much as the colored parts of the image though. I'm not going to slice them apart because that's too much work for me, but I will need to slice one of the tile images for math purposes. By extracting one of the tiles from the overall image, I can size it to 1.75" and I see that the scale is 32% of the original size. Now I know to resize your original group images to 32% of their original size and the tiles will print at 1.75" wide by 1.75" tall.
I'd like to briefly point out that if each tile was a separate image, there is opportunity to fit more than 12 per page. Right now there is three pages of 12 tiles each, but if it is possible to get it down to two pages that would save an entire sheet of label paper.
Here's the finished ZIP file, weighing in at a svelte 1.54 MB:
http://carcassonnecentral.com/forum/index.php?action=downloads;sa=view;down=168