Well what are there styleid's in the database?
The login you need to make sure the smfcookie name is specified in photopost and that everyone access's the forum and photopost on the same domain. SMF is not intuitive enough of a program to allow users the option to set cookie domains like other forums yet meaning you could set the domain to .domain.com to work with or without www so if someone goes to the gallery on domain.com and the forum on www.domain.com
of course the cookie is not carried over
I think that is probally your issue
Now the style like I said whats there styleid?
What your default theme id number set to in settings table
If the user's style is 0 or empty we set the style to your board default style number
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