First of all thank you for a great gallery plugin. Problem I had was that gallery on pages shows before any content (after header). Examning your source code I saw you write the html tags and echo some output from within the plugin code; this works, but due to the shortcode handling, the output is immediate (your should 'return' any output from a plugin); so I used ob_start(), ob_get_contents() and ob_end_clean() to return the output of the function to the core. While not ideal, this is a workaround that works OK. If you are interested, I can email you the changes.