posts and images from blogger look poor

I’m new to using wordpress but i’m putting together a secondary site based on vantage premium with the view to migrating my main site to this format, a bit easier updating than html in dreamweaver…..

This must have been covered and i’ve tried to find something but not even sure how to word the search term…..
I’ve pulled across old posts from blogger but the images are just kind of stacked on each other under the text and i’d like to get them into some kind of lightbox and present them well but not sure if i can do this retrospectively?

I pulled in 133 posts with between a handful of images in each to a few hundred in each so i’m looking for a solution that wont involve me removing all the images and re-uploading them.

I can’t add a link to specific post right now because of the “wp-content/themes/vantage/premium/extras/customizer/customizer.php on line 267” issue but once that’s sorted it’d be nice to make my galleries look pretty

Thanks,

Bryan.

URL: http://www.bryanfarrell.co.uk/photography-blog