See this Codex entry about attachment templates.
Hi Jogfly – I just sent a reply to this but my connection went down as I did. Not sure if it posted to you or not. Pls advise – I’d like to hear how you went with this – SEO outcomes specifically.
RE: Your initial post – I’ve been successful in adding meta descriptions to my gallery image attachment pages and have beefed up seo content on each – However, my query is whether these attachment pages do indeed get indexed by google – if not, have I just wasted my time trying to optimise:)
I look forward to hearing about your experiences regarding this.