Reviews for Don't "Accept" image/webp
Don't "Accept" image/webp by jscher2000
Review by Bjorn Roesbeke
Rated 4 out of 5
by Bjorn Roesbeke, 4 years agoTLDR: This addon genuinly tries to do what it promises but Firefox defaults + servers = useless addon.
The addon does something, but it's not resulting in refusal of webp images.
By clicking the "W" button on the toolbar, the sent "Accept" headers either include or don't include "image/webp", but it's of no use at all if the default following is "*/*".
It's possible to change the value of the "image.http.accept" key in "about:config" to (for example)
image/png,image/jpeg;q=1
but this addon will then not be able to change this value anymore.
Furthermore, websites such as Youtube (Google in general) just plain refuse to offer anything but webp, even if Firefox does not indicate support for it in the "Accept" header. You may need to fool these websites in assuming you're using an old browser by changing or emptying the "general.useragent.override" key.
Edited at 14/01/2024: changed rating 2»4; addon is not to blame for servers ignoring user preferences, as indicated in response by addon author.
The addon does something, but it's not resulting in refusal of webp images.
By clicking the "W" button on the toolbar, the sent "Accept" headers either include or don't include "image/webp", but it's of no use at all if the default following is "*/*".
It's possible to change the value of the "image.http.accept" key in "about:config" to (for example)
image/png,image/jpeg;q=1
but this addon will then not be able to change this value anymore.
Furthermore, websites such as Youtube (Google in general) just plain refuse to offer anything but webp, even if Firefox does not indicate support for it in the "Accept" header. You may need to fool these websites in assuming you're using an old browser by changing or emptying the "general.useragent.override" key.
Edited at 14/01/2024: changed rating 2»4; addon is not to blame for servers ignoring user preferences, as indicated in response by addon author.
Developer response
posted 4 years ago> The addon does something, but it's not resulting in refusal of webp images. ...
> Furthermore, websites such as Youtube (Google in general) just plain refuse to offer anything but webp, even if Firefox does not indicate support for it in the "Accept" header.
Hi Bjorn, the purpose of this extension is to discourage server farms from re-compressing PNG and JPEG images as WebP images on the fly to save bandwidth, since this complicates saving in the original formats. It is not a goal of this extension to prevent sites designed to serve WebP images from doing so.
> You may need to fool these websites in assuming you're using an old browser by changing or emptying the "general.useragent.override" key.
That might work, but some sites might serve less useful pages, so you'll have to test and see what is the best compromise.
> Furthermore, websites such as Youtube (Google in general) just plain refuse to offer anything but webp, even if Firefox does not indicate support for it in the "Accept" header.
Hi Bjorn, the purpose of this extension is to discourage server farms from re-compressing PNG and JPEG images as WebP images on the fly to save bandwidth, since this complicates saving in the original formats. It is not a goal of this extension to prevent sites designed to serve WebP images from doing so.
> You may need to fool these websites in assuming you're using an old browser by changing or emptying the "general.useragent.override" key.
That might work, but some sites might serve less useful pages, so you'll have to test and see what is the best compromise.
141 reviews
- Rated 5 out of 5by Sunny, a month agoIt doesn't always work on every webpage (half the time on Aliexpress), however it works most of the time.
Developer response
posted a month agoHi pjcamp, thank you for your report.
This extension makes a change to how Firefox requests images, but many sites ignore the change. If there is a specific site you want to mention, you can contact me by creating a new Github issue on https://github.com/jscher2000/dont-accept-webp/issues or emailing jscher2000@outlook.com.
On the other hand, if it fails on every single site, check for this issue: https://support.mozilla.org/kb/extensions-private-browsing
There also are some pages that give Firefox multiple format options (picture tag/source tags) and it selects WebP for some reason. I don't have a fix for that yet.- Rated 5 out of 5by Crowbar Scientist, 2 months ago
- Rated 1 out of 5by 64fanatic, 4 months agoNot working atm. Go to Youtube Community and try to save an image.
Developer response
posted 4 months agoHi, sites decide what format to serve based on different criteria. This extension only changes the "Accept" header. Some sites check the user agent instead (to see whether it's a modern browser). If you had the problem with a post on the Community tab of a YouTube channel, I see it, too. I don't think Google offers those images in alternate formats. (If I try to download one using the Internet Explorer 11 user agent, I still get WebP.) - Rated 4 out of 5by Firefox user 18285487, 5 months agoGreat idea. Lossless WebP is generally a superior alternative to Png (except it cannot handle HQs beyond 16k on a side), but when you get served a webp on a web site, there is a 95% chance it is just a Jpg that has gone through another round of lossy compression, a different type, at a lower bit rate = worse quality (fewer fine details).
In an ideal world, the digital master would be encoded as both Jpg/Png and Jxl, and the browser would have an option built in to preference one format over the other. JpegXl is the best new format. Jpeg2000 was decent but I don't think any browsers support it, and it even has a lossless format.
Unfortunately, this extension only works on some sites. Some are still sending me Webp,oravif (less often) and even twice I got a Jpegxl (I wish to force jpeg from these bossy CDNs that are enforcing inferior formats upon me). - Rated 5 out of 5by Firefox user 13807639, 7 months agoTipTop, endlich wieder vernünftige Datei-endungen
- Rated 5 out of 5by Dan, 7 months ago
- Rated 5 out of 5by oguz, 8 months ago
- Rated 5 out of 5by Shela, a year ago
- Rated 5 out of 5by Major Gear, a year agoThis addon installs easily and does what it says on the tin. I recommend this addon.
- Rated 5 out of 5by Stephen, a year agoFantastic! Does what it's supposed to and doesn't get in the way.
- Rated 5 out of 5by Firefox user 11803080, a year ago
- Rated 5 out of 5by Firefox user 18347256, a year agoExtremely useful and efficient, now I can save an image in it's original jpg or png format, instead of paying 2 conversions jpg-webp then webp-jpg. Should be the default when saving a jpg or png image.
- Rated 5 out of 5by Asmodeus, a year agothis is one of the most convenient and helpful add-on in the world, it made my life so much easier when using Reddit and is the sole reason I switched to Firefox.
- Rated 1 out of 5by Eru, a year ago
- Rated 5 out of 5by Firefox user 14506206, a year ago
- Rated 3 out of 5by CodeIcannot, a year agoAfter using this add-on for a long time, I'm only giving it 3 stars, because it's very unclear to me, if it's actually accomplishing anything...? There are lots of sites that keep pushing webp and avif files, even when this add-on is in use, and it feels like the number of those sites is increasing, all the time.
Developer response
posted a year agoUnfortunately, this add-ons is only effective on sites that pay attention to the "Accept" header. Other users have identified certain sites that ignore the change made by this add-on, such as NexusMods and PlayStation. These sites either no longer support legacy browsers, or require a legacy user agent (such as Internet Explorer 11) before sending legacy media formats. For cases like that, you could consider using a converter. I have one here on the Add-ons site called "Save webP as PNG or JPEG." - Rated 1 out of 5by Andrew, a year ago