You can also supply any length or percentage value, the cover keyword, or auto (which specifies that the image size is automatically determined using the intrinsic width and/or height of the image).įurther to this, all CSS properties are able to use the initial, inherit, and unset values. In this example, I use the contain keyword to specify the size of the background image.
In particular, you can use the background-size property to resize background images. You can also resize background images using CSS. thumbnail if you want the class applied to all elements that use that class.
Feel free to change img.thumbnail to just. You would need to use something like video.thumbnail in your stylesheet for video thumbnails. This prevents you from inadvertently applying the class to the wrong element in the event that another element uses a class of the same name.įor example, if a video element had class="thumbnail", the above class won't be applied to it.
By doing this, I'm specifying that only img elements that use the thumbnail class will have those styles applied. What I mean is, I've used img.thumbnail in the CSS. You might notice that I've prefixed the class name with img. Therefore, images with that class will be sized using those explicit dimensions instead. However, it also sets a class for thumbnails (called thumbnail) which explicitly sets their width and height. ImgInput.This sets all img elements to a maximum width of 100%. Let imgInput = document.getElementById('image-input')
Let's write the code to resize a user-uploaded image on the browser side 300x300. The first argument image can be created using the Image() constructor, as well as using any existing element. Resizing images in browser using canvas is relatively simple.ĭrawImage function allows us to render and scale images on canvas element. The HTML element is used to draw graphics, on the fly, via JavaScript. Image resizing in JavaScript - Using canvas element This is the preferred way to resize images without degrading the user experience programmatically.Īlso, we will learn how you can do this without needing to set up any libraries or backend servers. Then we will cover in great detail how you can resize, crop, and do a lot with images by changing the image URL in the src attribute.
If a user is manipulating a heavy image, it will take a lot of time to download transformed images from the server. The speed is critical for the user in these editors.