That said, I find all JS-based "zooming" of images bad. The simplest behaviour is the best here - just make the thumbnail a link to raw image directly. If you absolutely have to have that JS-based gallery, then for goodness' sake, don't do it with CSS background shenanigans - use the <img> tag, so that "right click + view image" works.
(To be fair to Gitlab, in this article "view image" works, and can be used to see images in full resolution.)
Alas, I'm pretty sure that half of this breakage are designers cargo-culting trends instead of focusing on usability; the other half is user-hostile designs purposefully making it harder for regular users to get to the URL of the actual image.
On a slightly similar vibe... if you're gonna take a picture of your laptop for the banner image on your web page, at least try cleaning the screen first. The dirty spots and greasy finger smudge in the top image make the whole page feel grimy, lol.
(1) The zoom animation takes too long, I want to see the screenshot
(2) After zooming, it's still difficult to read to my 33-year-old eyes. I want a fullscreen image.
(3) After finishing squinting at the screenshot, I scroll down to read more text only to have that text MOVE while I'm reading it as the screenshots animate back to their original positions.