Getting images to open in a new custom window

Hello loves!

I’m a new WordPress user and after a few hiccups where I ended up doing stupid things I’m up and running. However, this is causing me some headaches.

I’ve been meaning to do a photo gallery-type page for a while, and what better way to do it than integrate it into WP? What I want is a table of 100×100 thumbnails which when clicked open a new window with the full-size image in and a bit of a description (so it would have to be a HTML or PHP page rather than just the full-size image iteslf).

I’ve got a table working fine, centered and correctly-sized, and have no problems putting the thumbnail images into individual cells (I know sufficient HTML for this purpose). Linking to the images works fine – however, I’m stumped on how to open a new window from this link!

I would normally have used this tutorial but with the core pages being in PHP I’m at a loss as to what to do now.

https://www.strawdonkey.net
https://www.strawdonkey.net/gallery/

The gallery page is the offender – the first link is one where I’ve tried (and failed miserably) to splice javascript code into the link tag, and the second is a basic link which opens in the same window.

Can anyone help, or at least point me to a site that will show me a solution? I will be ok doing it all for myself so long as I have a decent reference ??

Thanks in advance!

Jonny