generated images do not work with GitHub Pages and static export

Link to the code that reproduces this issue

https://github.com/lifeiscontent/lifeiscontent.net

To Reproduce

I think due to the og images not having a file extension in the output, GitHub pages does not properly serve the generated images.

they work great with next dev but after deploying to GitHub pages it seems to serve the file as an octet-stream file

Current vs. Expected behavior

expected behavior would be to have file extensions during static export so static file providers handle it gracefully.

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:49 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T6000
  Available memory (MB): 65536
  Available CPU cores: 10
Binaries:
  Node: 22.17.1
  npm: 10.9.2
  Yarn: N/A
  pnpm: 10.13.1
Relevant Packages:
  next: 15.4.4 // Latest available version is detected (15.4.4).
  eslint-config-next: 15.4.4
  react: 19.1.1
  react-dom: 19.1.1
  typescript: 5.8.3
Next.js Config:
  output: export

Which area(s) are affected? (Select all that apply)

Output

Which stage(s) are affected? (Select all that apply)

Other (Deployed)

Additional context

No response

Start with the linked reproduction repository and compare generated OG image files and response handling under next dev and output: export. Verify the deployed GitHub Pages files and content types; done means static export produces image files with extensions that GitHub Pages serves as images rather than octet-stream files.