In the Chicago Tribune historical archives there are a number of article about your grandfather, including several related to his retirement in 1944. Maybe there were pictures taken then. There were no photos in the paper, but maybe a police fraternal organization would have some.

Have you seen those archives online? Your grandfather was involved in several newsworthy incidents, and he was wounded and injured several times too. If not, check out this site:

http://infoweb.newsbank.com/iw-search/we/HistArchive?p_actio...

search for "albert booth" and it brings up lots of articles. Of course, lots of them are false hits. You can narrow the search to specific decades which can help.