It looks like those jpg files don’t exist in your site as uploaded. Since you don’t have a 404.html, Pages is falling back to SPA behavior and returning the HTML content of your index page.
Make sure you’re uploading your entire site folder. Are you using direct upload from the dashboard, or Wranger, or Github?
Thank you for the quick answer! Indeed you are correct - I did something stupid, they were .gitignored, hence they didnt show up. I was confused aswell by the lack of 404 so i didnt really investigate. anyway, it now works, as you can see on the site haha.