Is there a way to add differentmeta tags to different pages(not included in template.html) and if there isn't how will search engine find my page - on images keywords?
I don't know about other search engines, but the biggest one, Google, doesn't even look at meta tags since it is subject to abuse/misuse.
Ok, but to display relevant google adsense ads I will need meta keywords tag.
I would think Google would ignore keywords for adsense for the same reason since some keywords will pay more than others so site owners can get money for them without having any of those on their site. Did you read somewhere that adsense requires using meta keywords?