Content-width where is it??

Hi Guys

Simple problem but I can’t seem to figure it out.

I’m using the “Tiled Gallery”, available in Jetpack 2.1, on my pages. however the gallery doesn’t fill the full width. It’s fixed at 625px.I’ve tried a number of things involving CSS and I’ve looked through all the files to find where I need to change the value but no look.The only thing I can consistently find is…

“It’s supposed to fill the entire width, but it defaults to 500px wide if the theme doesn’t define a content width, which it looks like yours doesn’t. You could try adding

if ( ! isset( $content_width ) )$content_width = 610;
to your theme’s functions.php.”

I’ve tried doing this but it still doesn’t work. That, I assume, means that the $content_width is defined elsewhere… anyone know where??