This metric mesures the number of bytes that could be saved by optimizing images.
Image optimization is generally one of the easiest way to reduce a page weight, and as a result, the page load time. Don't use Photoshop or other image editing tools, they're not very good for optimization. Use specialized tools such as Kraken.io or the excellent ImageOptim on Mac. For SVG images, you can use SVGOMG
The tools in use in YellowLabTools are not set to their maximum optimization power (JPEG quality 85), so you might be able to compress even more!
Please note that Yellow Lab Tools' engine (PhantomJS) is not compatible with image srcset (unless you use a polyfill). This can lead to incorrect page weight.
", + "message": "This metric measures the number of bytes that could be saved by optimizing images.
Image optimization is generally one of the easiest way to reduce a page weight, and as a result, the page load time. Don't use Photoshop or other image editing tools, they're not very good for optimization. Use specialized tools such as Kraken.io or the excellent ImageOptim on Mac. For SVG images, you can use SVGOMG
The tools in use in YellowLabTools are not set to their maximum optimization power (JPEG quality 85), so you might be able to compress even more!
Please note that Yellow Lab Tools' engine (PhantomJS) is not compatible with image srcset (unless you use a polyfill). This can lead to incorrect page weight.
", "isOkThreshold": 10240, "isBadThreshold": 122880, "isAbnormalThreshold": 307200, @@ -939,7 +939,7 @@ var policies = { "gzipCompression": { "tool": "weightChecker", "label": "Gzip compression", - "message": "Mesures the number of bytes that could be saved by compressing file transfers.
Gzip is a powerfull weight reducer and should be enabled on text-based assets in your server's configuration. Note that gzipping small files (< 1 KB) is arguable, and that some assets such as images should not be gzipped as they are already compressed. Here is a list of Content-Types that should be gzipped.
", + "message": "Measures the number of bytes that could be saved by compressing file transfers.
Gzip is a powerfull weight reducer and should be enabled on text-based assets in your server's configuration. Note that gzipping small files (< 1 KB) is arguable, and that some assets such as images should not be gzipped as they are already compressed. Here is a list of Content-Types that should be gzipped.
", "isOkThreshold": 5125, "isBadThreshold": 81920, "isAbnormalThreshold": 153600,