Need help with posting a gallery

I’m trying to add a gallery of pictures, just over 200. Here is what my code looks like:

Under the “Visual” tab, this is what it looks like:

But this is what it looks like with a preview…one column, no text, and a LOT of wasted space:

I tried installing a photo gallery plugin, but it duplicated every picture and does not include all the captions, and that will take forever to go through again one by one.

Any help would be greatly appreciated! If there’s something I need to do to the theme, please let me know.