The issue is that the header.png doesn't exist- when 302 Found status codes are returned, they just route to your hosting service's 404 page. The issue is actually most likely with InfinityFree- strange rate limiting, IP bans, and more. Their aggressive anti-bot measures can lead to inconsistent fetch behaviour- especially if your site is attracting traffic and people are pinging the image a lot (when the page loads). Or maybe your image is just missing. I recommend you switch to (literally) any other free hosting service- well established ones like Netlify, Vercel, and Fly.io. Also, check that the image actually exists! Normally it missing would 404, but there's no guarantees with InfinityFree.