- Decrease the amount of data to download.
- Improve page display speed.
- Decrease the energy impact related to the consultation of the site.
For image preview vignettes, use specific versions of them and not original images resized using their HTML attributes or CSS properties.
- Check that they do not have CSS
widthproperties which modify the apparent size of the images in relation to their actual dimensions.To do this, use "deactivate all CSS styles" using a web development tool to find images whose dimensions change after deactivating CSS styles.
- Also check that the dimensions indicated in the
heightattributes of the generated HTML code correspond to the actual dimensions of the image using a development tool.
For example, the following will be invalidated:
- An image of the type <img height="300" width="600" class="thumb"/> if the
.thumbclass imposes the CSS properties
- An image of the type <img height="100" width="200"/> if the actual dimensions of the image are 300px high and 600px wide.