is_single and the category/archive pages

Hi all,

I’m currently working on combination plugin of d13gallery and the hoverlightbox redux. I want to show the gallery only on the page that displays a single post.

so far:

if(!is_single()) {
        code to show thumb
} else {
        code to show gallery
}

this works on the index and on the single page. However, on the category and archive pages no thumb nor gallery is shown…

any ideas?

thanks,

Richard