slrpnk.net not giving file size in headers

I wanted to see the image size for this post before deciding to download the image. Normally curl -i returns a “content-length”, but not in this case:

$ curl -i 'https://slrpnk.net/pictrs/image/67127e8e-52ef-42ad-bf39-424b9052ef90.webp'
HTTP/2 200 
server: nginx
date: Mon, 22 Jan 2024 09:56:56 GMT
content-type: image/webp
last-modified: Sat, 20 Jan 2024 16:24:40 GMT
vary: Origin, Access-Control-Request-Method, Access-Control-Request-Headers
access-control-expose-headers: last-modified, content-type, accept-ranges, date, cache-control, transfer-encoding
cache-control: public, max-age=604800, immutable
accept-ranges: bytes
strict-transport-security: max-age=63072000
referrer-policy: same-origin
x-content-type-options: nosniff
x-frame-options: DENY
x-xss-protection: 1; mode=block

Seems like a bug, no?

UPDATE

I don’t do github so I reported the bug here in the off chance that someone notices.

UPDATE 2

Got “content-length: 0” this time:

$ curl -I 'https://slrpnk.net/pictrs/image/a1582706-199c-4994-9c4b-3057f85f3b97.webp'
HTTP/2 405 
server: nginx
date: Sun, 11 Feb 2024 09:39:44 GMT
content-length: 0
vary: Origin, Access-Control-Request-Method, Access-Control-Request-Headers
allow: GET
cache-control: public, max-age=60
access-control-expose-headers: allow