Resizing images

The image styles feature is meant to give the user a choice between a set of styling options provided by the system (i.e. by the developer or administrator who created it). There are also scenarios where the user should be able to freely set the width of an image. And that is where the image resize feature comes into play. It is implemented by the ImageResize plugin.

# Enabling image resizing

The image resize feature is enabled by default in the document editor build only. In order to enable it in other builds, you need to load the ImageResize plugin. Read more in the installation section.

# Methods to resize images

The editor offers different ways to resize images either by using “resize handles” or by using dedicated UI components — either a dropdown or standalone buttons.

The ImageResize plugin enables the four resize handles displayed over the selected image. The user can freely resize the image by dragging them. The feature can be configured to use either percentage (default) or pixel values.

The plugin also gives you an ability to change the size of the image through the on-click image toolbar. You can set an optional static configuration with resizeOptions and choose whether you want to use a dropdown or a set of standalone buttons.

# Using resize handles

In this case, the user is able to resize images by dragging square handles displayed in each corner of the image. Once image resizing is enabled, this option does not require any additional configuration.

Use the corner handles to resize the image and adjust it to the text as needed. You can also use the alignment options from the image toolbar to achieve the desired effect.

Images can also be pre-resized using styling, as observed below (the last three images are hard-set to 28% for the visual consistency of the article).

You can configure resizing images by handles in two different ways in the CKEditor 5 WYSIWYG editor:

• Either by installing the ImageResize plugin, which contains all needed features (ImageResizeEditing, ImageResizeHandles, ImageResizeButtons) as described in the installation of this guide.

• Or by installing the combination of ImageResizeEditing and ImageResizeHandles plugins, that won’t load the unnecessary ImageResizeButtons plugin:

import Image from '@ckeditor/ckeditor5-image/src/image';
import ImageResizeEditing from '@ckeditor/ckeditor5-image/src/imageresize/imageresizeediting';
import ImageResizeHandles from '@ckeditor/ckeditor5-image/src/imageresize/imageresizehandles';

ClassicEditor
    .create( document.querySelector( '#editor' ), {
        plugins: [ Image, ImageResizeEditing, ImageResizeHandles, ... ],
        ...
    } )
    .then( ... )
    .catch( ... );

Both ways enable resize handles by default.

# Using resize dropdown

In this case, the user is able to choose from a set of predefined options. These options can be displayed in form of a dropdown in the image toolbar available after the user clicks the image.

To use this option, you need to enable image resizing and configure the available resize options. Then add the dropdown to the image toolbar configuration.

const imageConfiguration = {
    resizeOptions: [
        {
            name: 'resizeImage:original',
            value: null,
            label: 'Original'
        },
        {
            name: 'resizeImage:40',
            value: '40',
            label: '40%'
        },
        {
            name: 'resizeImage:60',
            value: '60',
            label: '60%'
        }
    ],
    toolbar: [ ..., 'resizeImage' ]
}

Try out the live demo of the resize dropdown available in the image toolbar below.

# Using standalone resize buttons

In this case, the resize options are displayed in the form of separate buttons. The benefit of this solution is the smoothest UX as the user needs just one click to resize an image.

To use this option, you need to enable image resizing and configure the available resize options. Then add appropriate buttons to the image toolbar configuration.

const imageConfiguration = {
    resizeOptions: [
        {
            name: 'resizeImage:original',
            value: null,
            icon: 'original'
        },
        {
            name: 'resizeImage:50',
            value: '50',
            icon: 'medium'
        },
        {
            name: 'resizeImage:75',
            value: '75',
            icon: 'large'
        }
    ],
    toolbar: [
        ...,
        'resizeImage:50',
        'resizeImage:75',
        'resizeImage:original',
    ]
}

Try out the live demo of the individual resize buttons available in the image toolbar below :

# Disabling image resize handles

If, for some reason, you want to configure the editor in such a way that images can be resized only by buttons, you can do so by omitting the ImageResizeHandles plugin.

As a result, your plugin setup should look like this: plugins: [ 'ImageResizeEditing', 'ImageResizeButtons', ... ] as opposed to plugins: [ 'ImageResize', ... ].

This will enable the image resize feature only by means of the chosen UI: either a dropdown or standalone buttons) in the image toolbar.

import Image from '@ckeditor/ckeditor5-image/src/image';
import ImageToolbar from '@ckeditor/ckeditor5-image/src/imagetoolbar';
import ImageResizeEditing from '@ckeditor/ckeditor5-image/src/imageresize/imageresizeedititing';
import ImageResizeButtons from '@ckeditor/ckeditor5-image/src/imageresize/imageresizebuttons';

ClassicEditor
    .create( document.querySelector( '#editor' ), {
        plugins: [ Image, ImageResizeEditing, ImageResizeButtons, ImageToolbar, ... ],
        image: {
            resizeOptions: [
            {
                name: 'resizeImage:original',
                value: null,
                icon: 'original'
            },
            {
                name: 'resizeImage:50',
                value: '50',
                icon: 'medium'
            },
            {
                name: 'resizeImage:75',
                value: '75',
                icon: 'large'
            }
        ],
        toolbar: [
            // ...,
            'resizeImage:50',
            'resizeImage:75',
            'resizeImage:original',
        ]
        }
    } )
    .then( ... )
    .catch( ... );

# Markup and styling

When you resize an image, the inline width style is used and the <figure> element is assigned the image_resized class:

<figure class="image image_resized" style="width: 75%;">
    <img src="..." alt="...">
</figure>

The image_resized class is used to disable max-width assigned by the image styles if one is applied to this image. For instance, the “side image” style is defined like this:

.ck-content .image-style-side {
    max-width: 50%;
    float: right;
    margin-left: var(--ck-image-style-spacing);
}

And the max-width gets overridden by the following rule:

.ck-content .image.image_resized {
    max-width: 100%;
}

Another concern when styling resized images is that by default, CKEditor 5 uses display: table on <figure class="image"> elements to make it take up the size of the <img> element inside it. Unfortunately, browsers do not yet support using max-width and width on the same element if it is styled with display: table. Therefore, display: block needs to be used when the image is resized:

.ck-content .image.image_resized {
    display: block;
    box-sizing: border-box;
}

.ck-content .image.image_resized img {
    width: 100%;
}

.ck-content .image.image_resized > figcaption {
    display: block;
}

# Using pixels instead of percentage width

Using percentage widths ensures that the content stays responsive when displayed in places other than the WYSIWYG editor. When the user made an image take up, for example, 60% of the content’s width in the editor, if you ever change the width of the target page (where this content is displayed), the image will still take up 60% of that space. The same is true if the page is responsive and adjusts to the viewport’s width.

If you configured the editor to use pixel values, the image could take up, for example, too much space after you introduced a new layout for your website.

However, there are cases where pixel values may be preferred. You can thus configure the editor to use them by setting the config.image.resizeUnit option:

ClassicEditor
    .create( editorElement, {
        image: {
            resizeUnit: 'px',
            resizeOptions: [
                {
                    name: 'resizeImage:original',
                    label: 'Original',
                    value: null
                },
                {
                    name: 'resizeImage:100',
                    label: '100px',
                    value: '100'
                },
                {
                    name: 'resizeImage:200',
                    label: '200px',
                    value: '200'
                }
            ]
        }
    } )
    .then( ... )
    .catch( ... );

The following demo uses CSS to set up the fixed image aspect ratio, so a 200px wide image automatically gets the same height.

.ck.ck-content .image {
    position: relative;
}
.ck.ck-content .image img {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
}
.ck.ck-content .image::before {
    content: '';
    padding-top: 100%;
    display: block;
}

Check out the difference in the live demo below:

# Installation

The image resize feature is enabled by default in the document editor build only. To enable it in other editor builds, you need to install the ImageResize plugin, which contains all needed features (ImageResizeEditing, ImageResizeHandles, ImageResizeButtons):

import Image from '@ckeditor/ckeditor5-image/src/image';
import ImageResize from '@ckeditor/ckeditor5-image/src/imageresize';

ClassicEditor
    .create( document.querySelector( '#editor' ), {
        plugins: [ Image, ImageResize, ... ],
        ...
    } )
    .then( ... )
    .catch( ... );

# Common API

The ImageResize plugin registers:

• Image resize buttons (to use in the image toolbar).
• The 'resizeImage' command that accepts the target width.

# Contribute

The source code of the feature is available on GitHub in https://github.com/ckeditor/ckeditor5/tree/master/packages/ckeditor5-image.