Image Optimization returns 200 OK instead of 206 Partial Content for Range requests

Vercel Image CDN doesn't return a proper status code for range requests. In my app, sometimes Chrome do range requests for images when connection is slow and content changes (e.g. on navigations). Chrome first stores partial response as truncated cache entry and then the exact image is requested, it does a range request via Range and If-Range headers. Vercel properly handles those headers but, for some reason, returns 200 status code instead of 206 and because of that Chrome stores an empty response on its disk cache and restores it on subsequent visits.

Here is an example of response for curl:

curl -i   -H 'Range: bytes=12000-12000'   -H 'If-Range: Mon, 15 Jun 2026 14:31:00 
GMT'   'https://staging-app.playbook-kw.com/_next/image?url=https%3A%2F%2Fstaging-ap
i.playbook-kw.com%2Frails%2Factive_storage%2Fblobs%2Fredirect%2FeyJfcmFpbHMiOnsiZGF0
YSI6MzA2LCJwdXIiOiJibG9iX2lkIn19--20ccbd94aa6c886d88de0d03119080348adf307c%2Fgabriel
a-wasiewicz-cover.jpg&w=1920&q=85'
HTTP/2 200 
age: 2836389
cache-control: public, max-age=31536000, must-revalidate
content-disposition: attachment; filename="gabriela-wasiewicz-cover.jpg"
content-range: bytes 12000-12000/252693
content-security-policy: script-src 'none'; frame-src 'none'; sandbox;
content-type: image/jpeg
date: Thu, 13 Aug 2026 00:29:01 GMT
last-modified: Mon, 15 Jun 2026 14:30:00 GMT
server: Vercel
strict-transport-security: max-age=63072000
vary: Accept
x-vercel-cache: HIT
x-vercel-id: fra1::s8fw7-1789417331576-12beb0976691
content-length: 1

As you can see it returns 200 status code for content-length: 1.

Here is another example where it doesn't hit cache on CDN:

curl -i   -H 'Range: bytes=12000-12000'   -H 'If-Range: Mon, 15 Jun 2026 14:30:00 
GMT'   'https://staging-app.playbook-kw.com/_next/image?url=https%3A%2F%2Fstaging-ap
i.playbook-kw.com%2Frails%2Factive_storage%2Fblobs%2Fredirect%2FeyJfcmFpbHMiOnsiZGF0
YSI6MzA2LCJwdXIiOiJibG9iX2lkIn19--20ccbd94aa6c886d88de0d03119080348adf307c%2Fgabriel
a-wasiewicz-cover.jpg&w=1920&q=80'
HTTP/2 200 
age: 0
cache-control: public, max-age=31536000, must-revalidate
content-disposition: attachment; filename="gabriela-wasiewicz-cover.jpg"
content-range: bytes 12000-12000/202870
content-security-policy: script-src 'none'; frame-src 'none'; sandbox;
content-type: image/jpeg
date: Mon, 14 Sep 2026 20:22:49 GMT
last-modified: Mon, 15 Jun 2026 14:30:00 GMT
server: Vercel
strict-transport-security: max-age=63072000
vary: Accept
x-vercel-cache: MISS
x-vercel-id: fra1::6hcdh-1789417369461-bf67c5aca929
content-length: 1

curl -i -H 'Range: bytes=12000-12000' -H 'If-Range: Mon, 15 Jun 2026 14:31:00 GMT' 'https://staging-app.playbook-kw.com/_next/image?url=https%3A%2F%2Fstaging-ap i.playbook-kw.com%2Frails%2Factive_storage%2Fblobs%2Fredirect%2FeyJfcmFpbHMiOnsiZGF0 YSI6MzA2LCJwdXIiOiJibG9iX2lkIn19--20ccbd94aa6c886d88de0d03119080348adf307c%2Fgabriel a-wasiewicz-cover.jpg&w=1920&q=85' HTTP/2 200 age: 2836389 cache-control: public, max-age=31536000, must-revalidate content-disposition: attachment; filename="gabriela-wasiewicz-cover.jpg" content-range: bytes 12000-12000/252693 content-security-policy: script-src 'none'; frame-src 'none'; sandbox; content-type: image/jpeg date: Thu, 13 Aug 2026 00:29:01 GMT last-modified: Mon, 15 Jun 2026 14:30:00 GMT server: Vercel strict-transport-security: max-age=63072000 vary: Accept x-vercel-cache: HIT x-vercel-id: fra1::s8fw7-1789417331576-12beb0976691 content-length: 1

curl -i -H 'Range: bytes=12000-12000' -H 'If-Range: Mon, 15 Jun 2026 14:30:00 GMT' 'https://staging-app.playbook-kw.com/_next/image?url=https%3A%2F%2Fstaging-ap i.playbook-kw.com%2Frails%2Factive_storage%2Fblobs%2Fredirect%2FeyJfcmFpbHMiOnsiZGF0 YSI6MzA2LCJwdXIiOiJibG9iX2lkIn19--20ccbd94aa6c886d88de0d03119080348adf307c%2Fgabriel a-wasiewicz-cover.jpg&w=1920&q=80' HTTP/2 200 age: 0 cache-control: public, max-age=31536000, must-revalidate content-disposition: attachment; filename="gabriela-wasiewicz-cover.jpg" content-range: bytes 12000-12000/202870 content-security-policy: script-src 'none'; frame-src 'none'; sandbox; content-type: image/jpeg date: Mon, 14 Sep 2026 20:22:49 GMT last-modified: Mon, 15 Jun 2026 14:30:00 GMT server: Vercel strict-transport-security: max-age=63072000 vary: Accept x-vercel-cache: MISS x-vercel-id: fra1::6hcdh-1789417369461-bf67c5aca929 content-length: 1