December 3, 2021 at 10:24 am #45723Rob SteadGuest
The W3 Total Cache Image Service looks like a great idea but I’m failing to understand how to use it.
I’ve converted the images but they’re still showing as jpgs.
I’ve cleared the cache and done the other things suggest.
What am I failing to understand? Here is an example: https://www.robstead.co.uk/vision2020/
I have the Pro version on another site and it’s the same.
Thanks, RobDecember 3, 2021 at 1:38 pm #45734
Thank you for reaching out and for using W3 Total Cache for webp conversion.
As I can see your images are being served from the CND
If you opened the image in the new tab:
The image is loading and the content type is jpeg
If you change the extension to .webp:
The CDN will state that the file is missing.
If I change the URL to your DNS:
This will throw the 404 not found.
All of the above means that the images are not converted so I would suggest reaching out to yoru hosting provider and checking if the ImageMagick is enabled and allowing webp.
Thanks!December 6, 2021 at 9:49 am #45738Rob SteadGuest
Thank you Marko.
I’m hosting my own vpn and have since installed ImageMagick.
When you say allows webp is that something I need to do within ImageMagick or somewhere else? I can view webp images from a different site but on the same server: https://www.kitscottage.uk/wp-content/uploads/2021/11/FBHouseView1200-54percent.webp
After installing ImageMagick I did try disabling and re-enabling the extension.
RobDecember 6, 2021 at 9:56 am #45801
Thank you for the feedback.
You can check more details in this article.
I do see that when I change the extension to .webp, the images are showing in the correct webp format.
Have you tried purging the CDN since all images are served from the CDN?
Thanks!December 7, 2021 at 8:42 am #45817Rob SteadGuest
I did manage to install the missing webp from ImageMagick supported formats but even after doing this and purging everything from CDN it’s still showing the original jpg image rather than the webp.
Is there something I need to do to kick it into doing so? Or am I missing something in my understanding? I was assuming, like with cdn, the image URLs will simply change to show the webp version.
RobDecember 7, 2021 at 8:58 am #45837
Thank you for your feedback.
W3 Total Cache uses the rewrite rules in place in your .htaccess/nginx file.
All images converted with the Image Service tool are sent to a third-party server maintained by the W3 Total Cache team which reduces resource consumption and allows for a large number of conversions in environments where resources can be limited such as shared hosting. Images sent to the W3TC server for conversion are only held temporarily and no permanent information is kept on the server regarding the images.
WebP optimizations with the Image Service tool do not replace the original image file and all conversions can be reverted without any loss of data.
Ideally, once the image is converted, you should see the content-type: image/webp header when inspecting the source.
You should also check if the .htaccess/nginx conf has the BEGIN W3TC WEBP rules at the top of the file, before any other rules.
There is also a possibility that you are missing additional image sizes, so please check our article, and under the Troubleshooting section check the Missing Additional Image Sizes for more details.
Thanks!December 8, 2021 at 7:08 am #45877Rob SteadGuest
I think I understand now.
My understanding is W3 Total Cache Image Service ‘simply’ converts the images making them available and the switch is done via a rewrite rule in Apache (in my case). But because I’m using a CDN then I can’t control this.
I was working on the assumption W3 Total Cache Image Service would handle the switch (like it does for CDN).
I also don’t quite understand why if images are sent to your server to be converted why you need webp format support for ImageMagic. I only mention this in case it’s useful feedback. It took me some time getting this to work and I find Ubuntu updates then remove this format support.
I’ve now started to manually change the images whenever I spot one.
Thanks for your help in making this clear.
RobDecember 8, 2021 at 7:15 am #45883
You are most welcome and I am glad the webp conversion procedure is more clear now.
As for your question regarding the ImageMagic, I’ll try to explain.
One image conversion equals one request to the API server to convert the image. Depending on the website, a single image can have the original image, and 3-6 resized images (thumbnails) so that can multiply a single request to API server 6 times. More requests mean slower conversion and that’s where Image Magic kicks in.
I hope this explains the reason for this and let me know if you have any other questions.
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