[Bug]: Latest Frame API sets invalid Content-Type

[maksz42]

Checklist

• I have updated to the latest available Frigate version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in incognito mode to rule out problems with any third party extensions or plugins I have installed.

Describe the problem you are having

https://docs.frigate.video/integrations/api/latest-frame-camera-name-latest-extension-get
The API sets invalid Content-Type as image/Extension.{extension}. Expected image/{extension}.
Applies to all extensions except jpeg, which has correct Content-Type.

$ curl -s -I -X GET http://frigate:5000/api/mycam/latest.webp
HTTP/1.1 200 OK
Server: nginx/1.27.4
Date: Sun, 17 Aug 2025 01:09:25 GMT
Content-Type: image/Extension.webp
Content-Length: 22382
Connection: keep-alive
cache-control: no-store

$ curl -s -I -X GET http://frigate:5000/api/mycam/latest.jpeg
HTTP/1.1 200 OK
Server: nginx/1.27.4
Date: Sun, 17 Aug 2025 01:49:18 GMT
Content-Type: image/jpeg
Content-Length: 39018
Connection: keep-alive
cache-control: no-store

Content-Type was correct in Frigate 0.15.1

Steps to reproduce

1. Send a request to /api/:camera_name/latest.:extension

Version

0.16

In which browser(s) are you experiencing the issue with?

No response

Frigate config file

n/a

docker-compose file or Docker CLI command

n/a

Relevant Frigate log output

n/a

Relevant go2rtc log output

n/a

Operating system

Other Linux

Install method

Docker Compose

Network connection

Mixed

Camera make and model

n/a

Screenshots of the Frigate UI's System metrics pages

n/a

Any other information that may be helpful

The bug is most likely related to this: mobilityhouse/ocpp#447

frigate/frigate/api/defs/query/media_query_parameters.py

Lines 8 to 12 in 856aab8

	class Extension(str, Enum):
	webp = "webp"
	png = "png"
	jpg = "jpg"
	jpeg = "jpeg"

And jpeg works because of this:

frigate/frigate/api/media.py

Line 156 in 856aab8

mime_type = "jpeg"

And I've never touched FastAPI, and I might be wrong, but the docs says Content-Type is set automatically based on media_type, so explicitly setting Content-Type seems redundant.

[inkeep-ai-assistant[bot]]

The Latest Frame API endpoint you're referring to is documented in the Frigate HTTP API (1)(2). The endpoint accepts various image extensions including webp, png, jpg, and jpeg (3)(4).

Based on your bug report, you're experiencing an issue where the Content-Type header is incorrectly set to image/Extension.webp instead of the expected image/webp format for non-jpeg extensions. This appears to be a regression from Frigate 0.15.1 to 0.16.

The API endpoint GET /{camera_name}/latest.{extension} is designed to return the latest frame from a specified camera in the requested format (1)(2). The supported extensions are webp, png, jpg, and jpeg (3).

Since this is a bug report about incorrect Content-Type headers in the HTTP response, and the issue appears to be in the FastAPI implementation rather than the documented API specification, you should report this on the Frigate GitHub repository for the development team to address.

📚 Sources:

1. GET /{camera_name}/latest.{extension}
2. Latest Frame
3. Extension
4. Extension

---

Have another question? Just tag @inkeep.

[hawkeye217]

Thanks, this is fixed in #19555

[maksz42]

I don't want to nitpick, but with

frigate/frigate/api/media.py

Line 156 in 856aab8

mime_type = "jpeg"

removed, .jpgwill result in an invalid MIME type image/jpg. It should be image/jpeg.
Also, in Python 3.11 StrEnum was introduced, which behaves like class MyEnum(str, Enum) pre 3.11 when it comes to string formatting, if that comes in handy.

[NickM-27]

image/jpg is perfectly valid according to browser spec https://developer.mozilla.org/en-US/docs/Web/Media/Guides/Formats/Image_types#common_image_file_types

[maksz42]

https://developer.mozilla.org/en-US/docs/Web/Media/Guides/Formats/Image_types#jpeg_joint_photographic_experts_group_image
I see only image/jpeg. Am I missing something?

[NickM-27]

image/jpeg is technically preferred but both are handled by modern browsers like is shown in the table.

[maksz42]

I'm pretty sure that image/jpg is invalid and browsers don't perform MIME sniffing anymore, but I've checked, and Firefox and Chromium handle it correctly.

[hawkeye217]

This has been improved further in #19708