Police "mug shots" are a public record but, then they're not, if the Sheriff so decides. So goes the two-sided Attorney General Opinion on the public releasability of police booking photos, seemingly like every other government record subject to Government Code section 6254. I announced this somewhere recently but now I've found the California AG Opinion that references public access to copies of arrestee photos. AG Bill Lockyer delivered this 2003 Opinion in response to Contra Costa Sheriff Warren Rupf's request inquiring whether photos must be released under the California Public Records Act. It's not a sharp-edged biting opinion. But it'll have to do. And I think there's enough support for release to wave this Opinion in front of "your Sheriff here".
Lockyer concludes,
A sheriff has discretion to furnish copies of photographs of arrested persons, commonly known as "mug shots," in response to a request from a member of the general public, including the news media; however, once a copy is furnished to one member of the general public, a copy must be made available to all who make a request. Read and download this short Opinion