Sneakers E-commerce Page (HTML, SCSS, and Vanilla JS)

What are some possible ways to get the white overlay on the lightbox thumbnails? Strangely, I wasn't able to do this. I could create an overlay when selected or on a div but for some reason, I ran into a mental block trying to creating the desired overlay on hover for an <img>.

Aside from this, I would love any feedback. I'm starting to apply for jr. dev positions and am curious what experienced devs think when seeing my code. Are there any red flags? Is there something I should be doing? Do I look like a complete beginner?

**I have updated my solution to fix some accessibility concerns and HTML Validation issues.