My Web page uses jQuery to show the following lightbox pop-ups:

It uses the following scripts:

2. <script src="https://code.jquery.com/jquery-1.12.4.min.js" integrity="sha384-nvAa0+6Qg9clwYCGGPpDQLVpLNn0fRaROjHqs13t4Ggj3Ez50XnGQqc/r8MhnRDZ" crossorigin="anonymous"></script>
3. <script type="text/javascript" src="../src/jquery.flashy.min.js"></script>
4. <script type="text/javascript" src="../src/jquery.flashy.js"></script>
5. <script type="text/javascript" src="assets/js/main.js"></script>

How would I begin to make my pop-up (the enlarged image) look less plain, please? I have seen prettier ones that are more pleasing to the eye - do I need to modify one, or more, of those jQuery files?

Thank you.