How to do This Gallery Contains X amount of photos in 3.5.1

bump, I really need this done. I’m hoping this might cut load time on my wp.

Also, how do you change the size of the image on the attachment page?

Example:
https://freshgrocerygetters.com/euro-meet-photoshoot-2/dsc_0300/

You’ll need to contact the developers of your theme for any help – these forums only support themes from the repository on this site. Further, you may not be aware of it, but your theme is not released under GPL licensing which is not in keeping with WP policy and philosophy. I’d actually suggest you find another theme.

I have changed my theme and removed that theme. Can you assist me now? That would be great, thank you!

Even after changing to the twenty twelve theme, this option for gallery formatting and such will not pop up.