Depends on if you need the lightbox plugin. Personally I do not use a lightbox unless you have a gallery page, then I would find a solution that only affects that page. It just ends up bringing in too many other unwanted images (such as logos and whatnot)
If you do not feel you necessarily need or want it, then yes, deactivate it.
BUT some lightbox plugins that I have come across in the past offer a way to switch it off for a particular image.
On your image, you have a link. if you add
rel=”[insert random word here]” within the anchor tag (right after the href attribute
Like the following
<a href="link-source" rel="insertrandomwordhere" >
then it will occupy the rel attribute so that lightbox cannot be loaded onto it.
but I am not certain that would work, it has always been hit and miss for me.