#RESPONSIVELY SIZE MODIFY IMAGE IN HTML HOW TO#

We simply add the width of the images after the file name, such as 730w, 610w, and 350w. The srcset attribute can be used in the and elements. This is where the responsive srcset, sizes, and media attributes come to the rescue. Serving an unscaled image will slow performance, increase the overall page size, and waste bandwidth. While using CSS to scale the image to fit across all devices does make the image responsive, which in our case is accomplished by using the img-fluid class, this would lead to a significant amount of unnecessary data being delivered. The problem with using the element above is that it will result in a single image being delivered across all devices. That is why it is common to see the class attribute to style the image instead, for example: The width and height attributes can define src size, but this could lead to an image larger than the device viewing it. However, it is highly recommended to add the alt attribute as this attribute is important for search engines and screen readers. If an absolute path is defined, as shown above, the browser will make a request using the scheme and hostname of website where the element is placed. The src attribute will let the browser know where to make the image request. To cover the basics, all that is actually required to insert an image is the tag and src attribute, for example:

#RESPONSIVELY SIZE MODIFY IMAGE IN HTML HOW TO#

How to use the srcset, sizes, and media attributes In all cases the element needs to be a direct child of the element. The sizes attribute can be used in the and elements, whereas the media attribute can be used in the element but not the element. However, the sizes attribute allows an image size to defined either alone or in relation to a media condition. Both allow different display sizes to be defined through various media conditions. This attribute can be used in the and elements.īoth the sizes and media attributes are nearly identical. This can be done by defining the absolute or relative path to the images and optionally the pixel density descriptors (e.g. The srcset attribute allows image sources to be defined. This offers browsers the ability to display a specific image when a rule is met. The srcset, sizes, and media attributes allow the and elements to be extended by offering the browser additional information, such as different image sources as well as different display sizes and media conditions. What are the srcset, sizes, and media attributes? As you may recall from our Image CDN article, images take up 51% of the average web page size, which means serving scaled images is critical to reduce your web page sizes. This is advantageous because of the significant performance improvements that can be gained.

Instead of taking a single image and only making it responsive with CSS, which is then delivered to all devices, you can deliver completely different images based on the requesting device. This allows you to further optimize your image delivery to improve the overall performance of your website or application. Responsive image techniques, such as the srcset, sizes, and media HTML attributes, allow different scaled images to be delivered based on the size and resolution of the accessing device.

Responsively size modify image in html