Don't "Accept" image/webp by jscher2000

Firefox usually sends websites an indicator that it can handle WebP-format images, and this may encourage sites to send images in WebP formats. This extension strips out that indicator from requests (more specifically, the Accept header) so sites are more likely to send JPEG and PNG format images.

Version 0.7 adds the option to also strip image/avif from the Accept header.

Notes:

(1) Although broad permission is needed for this extension to modify the Accept header, no data is read from requests, responses, or web pages.

(2) This extension monitors and edits request headers using the onBeforeSendHeaders API. There is a possibility of a conflict with other extensions that use the same API, which can lead to inconsistent results for both extensions.

Note: since Firefox 68, users cannot directly edit the network.http.accept.default preference, so if you found an old solution of removing image/webp from that preference, you've found the right new workaround.