Check out the pictures of ticks on this website
Tick images on other websites
University of Bristol tick identification - Images and important points to help researchers and vets identify ticks of veterinary importance
UK Tick Recording Scheme – Information on how to collect ticks and send them for identification and mapping. At the bottom of the page is a link to images and descriptions of British ticks and exotic ticks.
Dartmoor tick watch - Images of ticks collected on Dartmoor. This site also includes high resolution images that show the detail of tick mouthparts. The creator of this site has now retired but has left the material available.
Tick borne encephalitis web site - Several images, some high resolution, some computer simulations and some good comparison of different stages to show differences in sizes.
Lyme Borreliosis Foundation Hungary where there is a brilliant animation of how NOT to remove a tick!