target="_blank" not working correctly

https://www.preferredcustoms.com/incurve-wheels/incurve-ic-s10-wheels/

For example, for the first image of the wheels at the top left of the group, I would like it when you click on the image, it opens to this…..
https://www.preferredcustoms.com/wp-content/uploads/2012/12/Incurve-Wheels-Incurve-IC-S10-Wheels-Incurve-ICS10-Wheels-matte-silver-concave-wheels-1.jpg

But instead it opens a pop-up in the same window.

I’ve been testing it with the first two wheel images…. I have the thumbnail image of each on this page, with a link for a full size version of that image. I believe I have the <img src=”(thumbnail image URL)”> entered correctly, but it still opens a pop-up instead of going to a new page…..

I have looked at the source code from other websites with images/links that function this way, and I don’t see any difference in the code.

Is there something with the setting in WordPress that needs to be modified to disable the pop-up, or is there another way I need to be writing the code?