Obtaining images for publication purposes will require high resolution, digital images of 300-600 ppi (pixels per inch) and permission to print from copyright owners of the image. Price or fee will vary depending on whether the image is b/w or colour, place of publication and distribution plans (print runs and location of distribution - Europe, North America or Global). Some sites listed have high resolution images available. You will need to contact owner of site to obtain permission for publishing or use in your thesis. Using images for teaching or course assignments does not require permission, it fall under fair dealing in Canada.