alt Hacker NewsDanbooru[1] and Danbooru-derived image boards handle this perfectly, and are a genuine pleasure to browse relative to the awful experience that is pinterest. There is empty space between images, and that is fine. You don't need to occupy every pixel in the screen to begin with, that's why we have these magical things called "margins", elements need room to breathe in the first place.
[1]https://safebooru.donmai.us/ (note: this is a "safe" subset of danbooru for reference, but it is still not safe for work)
How is that better? It's still a grid of images that seem to be constrained to a more or less rectangular grid. I'm thinking more of a dynamic grid where there is a mix of sizes of horizontal and vertical images.