Does srcset optimizes image file size?

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1

Hello,

I have a files section to upload images. Some of the ones uploaded by the editor have been very big, around 9.000 x 5.000px and 2.5MB size. They have been told already that the images should be smaller but I tried to use srcsets to decrease the image size.

Here is my config.php file:

return [
    'debug'  => true,
    'languages' => true,
    'thumbs' => [
    'srcsets' => [
      'default' => [
        '800w' => ['width' => 800, 'quality' => 80],
        '1024w' => ['width' => 1024, 'quality' => 80],
        '1440w' => ['width' => 1440, 'quality' => 80],
        '2048w' => ['width' => 2048, 'quality' => 80]
      ]
    ]
    ]
];

And I call them in the template just like this:

$html .= '<img src="' . $image->resize(1024)->url() . '"';
$html .= 'srcset="' . $image->srcset() . '">';

I realized the page size in the frontend is not decreasing, downloading a huge amount of assets. Every image has almost the same original size of 2.5MB.

I tried many different things in case it is not picking up the correct images but seems like that is working. Then I checked the media folder and the images are there followed by their corresponding extension regarding the quality and width but looked at their specs they seem to be identical.

I am not sure if this is the normal srcset behavior and it is not a good option to reduce the file size of an image but I al also surprised the generated images are the same resolution.

2

If the image have the exact same pixel sizes but just different files names, then for some reason Kirby cannot create the thumbs.

Are you using the default gd thumbs driver?

3

Yes, I haven’t configured any so it is using the default.

4

Is gd enabled on your server? Check with phpinfo().

If yes, check if you get any error messages in your server error or php error logs.

I’m not sure if there is a limit to what files sizes gd can handle.

It might be worth checking if normal size images are resized correctly.

On a side note:
It might be worth noting that unless you use full-width images only, srcset must always be accompanied by a sizes attribute, otherwise the wrong image sizes will be chosen. See also:

5

In the phpinfo() was enabled.
Then I checked the error logs and I found several errors like this:

[06-Sep-2022 13:18:33 UTC] PHP Fatal error:  Allowed memory size of 134217728 bytes exhausted (tried to allocate 32768 bytes) in /Applications/MAMP/htdocs/websitename/kirby/vendor/filp/whoops/src/Whoops/Util/Misc.php on line 1

That means the size of the images is too big for the server memory to handle that image scaling process?

Thanks for pointing about the sizes attribute!

6

That might well be. If you can install ImageMagick or if it is available, I’d switch to that, more performant. You might have to check your memory settings as well.