180MB is probably fine for most servers (especially CDNs), to be honest. My M1 MacBook with 16 gigabytes of RAM is struggling to load/display the data though.
> GitHub Pages sites have a soft bandwidth limit of 100 GB per month.
> If your site exceeds these usage quotas, we may not be able to serve your site, or you may receive a polite email from GitHub Support suggesting strategies for reducing your site's impact on our servers, including putting a third-party content distribution network (CDN) in front of your site, making use of other GitHub features such as releases, or moving to a different hosting service that might better fit your needs.
A photo could work as a quick preview indeed. As another idea for large content spiking in popularity, another solution may be something like webtorrent, or whatever peertube uses
Or a vector map, loading data as needed for the region you're zooming into
More civilized would be a photo snapshot + optional link to 180MB download for interactive UX.