# Images

> Documentation and examples for opting images (via `<b-img>` component) into responsive behavior
> (so they never become larger than their parent elements), optionally adding lightweight styles to
> them — all via props. Support for rounded images, thumbnail styling, alignment, and even the
> ability to create blank images with an optional solid background color.

## Image src resolving

The `src` prop (and `blank-src` prop of `<b-img-lazy>`), out of the box, works only with
absolute/fully-qualified-domain-name URLs. If you are using project assets as image sources, please
refer to [Component img src resolving](/docs/reference/images) for configuring `vue-loader` to
understand custom component props that specify image sources.

## Responsive images

Images in BootstrapVue can be made responsive with the `fluid` prop (which sets
`max-width: 100%; height: auto;` via CSS classes) so that it scales with the parent element - up to
the maximum native width of the image.

```html
<div>
  <b-img src="https://picsum.photos/1024/400/?image=41" fluid alt="Responsive image" />
</div>

<!-- b-img-fluid.vue -->
```

To make a fluid image that will grow to fill the width of it's container, use the `fluid-grow` prop.
Note this may cause bluring on small bitmap images.

```html
<div>
  <h5>Small image with <code>fluid</code>:</h5>
  <b-img src="https://picsum.photos/300/150/?image=41" fluid alt="Fluid image" />

  <h5 class="my-3">Small image with <code>fluid-grow</code>:</h5>
  <b-img src="https://picsum.photos/300/150/?image=41" fluid-grow alt="Fluid-grow image" />
</div>

<!-- b-img-fluid-grow.vue -->
```

Use the `block` prop to force the image to display as a block element rather than the browser
default of inline-block element.

**Note:** _In Internet Explorer 10, SVG images with `fluid` are disproportionately sized. To fix
this, add the style `width: 100% \9;` where necessary. This fix improperly sizes other image
formats, so Bootstrap V4 doesn’t apply it automatically._

## Image thumbnails

You can use prop `thumbnail` to give an image a rounded light border appearance.

```html
<b-container fluid class="p-4 bg-dark">
  <b-row>
    <b-col>
      <b-img thumbnail fluid src="https://picsum.photos/250/250/?image=54" alt="Image 1" />
    </b-col>
    <b-col>
      <b-img thumbnail fluid src="https://picsum.photos/250/250/?image=58" alt="Image 2" />
    </b-col>
    <b-col>
      <b-img thumbnail fluid src="https://picsum.photos/250/250/?image=59" alt="Image 3" />
    </b-col>
  </b-row>
</b-container>

<!-- b-img-thumbnail.vue -->
```

## Rounded corners

You can control which corners are rounded by setting the rounded prop to one of the following
values:

- `true` (or prop present with no value): round all corners
- `false` (or prop not present): no explit rounding or corners (default)
- `'top'`: round the top corners
- `'right'`: round the right corners
- `'bottom'`: round the bottom corners
- `'left'`: round the left corners
- `'circle'`: make a circle (if square image) or oval (if not square) border
- `'0'`: explicity turn off rounding of corners

```html
<template>
  <div>
    <b-img v-bind="mainProps" rounded alt="Rounded image" />
    <b-img v-bind="mainProps" rounded="top" alt="Top-rounded image" />
    <b-img v-bind="mainProps" rounded="right" alt="Right-rounded image" />
    <b-img v-bind="mainProps" rounded="bottom" alt="Bottom-rounded image" />
    <b-img v-bind="mainProps" rounded="left" alt="Left-rounded image" />
    <b-img v-bind="mainProps" rounded="circle" alt="Circle image" />
    <b-img v-bind="mainProps" rounded="0" alt="Not rounded image" />
  </div>
</template>

<script>
  export default {
    data() {
      return {
        mainProps: { blank: true, blankColor: '#777', width: 75, height: 75, class: 'm1' }
      }
    }
  }
</script>

<!-- b-img-rounded.vue -->
```

## Aligning images

Align images with the boolean props `left` (floats left) `right`(floats right), and `center` (auto
left+right margins). You can also center images by placing them in a container that has the class
`text-center`.

**Left an Right aligned (float):**

```html
<div class="clearfix">
  <b-img left src="https://picsum.photos/125/125/?image=58" alt="Left image" />
  <b-img right src="https://picsum.photos/125/125/?image=58" alt="Right image" />
</div>

<!-- b-img-left-right.vue -->
```

**Center aligned (block):**

```html
<div>
  <b-img center src="https://picsum.photos/125/125/?image=58" alt="Center image" />
</div>

<!-- b-img-center.vue -->
```

Note: `left` takes precedence over `right` which takes precedence over `center`.

## Blank (or solid color) Images

`<b-img>` provides built-in support for generating blank images (transparent by default) of any
width and height, by setting the `blank` prop, and specifying `width` and `height` values (in
pixels). You can apply any of the other `<b-img>` props to change the style/behavior of the generted
image.

Use the `blank-color` prop to set the blank image color. The `blank-color`prop can accept any CSS
color value:

- Named colors — i.e. `orange` or `blue`
- Hex colors — i.e. `#FF9E2C`
- RGB and RGBa colors — i.e. `rgb(255, 158, 44)` and `rgba(255, 158, 44, .5)`
- HSL and HSLa colors — i.e. `hsl(32, 100%, 59%)` and `hsla(32, 100%, 59%, .5)`

The default `blank-color` is `transparent`.

```html
<template>
  <div>
    <b-img v-bind="mainProps" alt="Transparent image" />
    <b-img v-bind="mainProps" blank-color="#777" alt="HEX shorthand color image (#777)" />
    <b-img v-bind="mainProps" blank-color="red" alt="Named color image (red)" />
    <b-img v-bind="mainProps" blank-color="black" alt="Named color image (black)" />
    <b-img v-bind="mainProps" blank-color="#338833" alt="HEX color image" />
    <b-img v-bind="mainProps" blank-color="rgba(128, 255, 255, 0.5)" alt="RGBa color image" />
    <b-img v-bind="mainProps" blank-color="#88f" alt="HEX shorthand color (#88f)" />
  </div>
</template>

<script>
  export default {
    data() {
      return {
        mainProps: { blank: true, width: 75, height: 75, class: 'm1' }
      }
    }
  }
</script>

<!-- b-img-blank.vue -->
```

**Notes:**

- In blank image mode, if only one of width or height is set, the image will be have both width and
  height set to the same value.
- In blank image mode, if width and height are not set, both width and height will internally be set
  to 1.
- The `blank` prop takes precedence over the `src` prop. If you set both and later set `blank` to
  `false` the image specified in `src` will then be displayed.
- Blank images are rendered using SVG image data URLs.
- The `width` and `height` props will also apply the `width` and `height` attributes to the rendered
  `<img>` tag, even if `blank` is not set.

## Lazy Loaded images

> Use our complementary `<b-img-lazy>` image component (based on `<b-img>`) to lazy load images as
> they are scrolled into view (or within `offset` pixels of the viewport).

Lazy loading images relies on the document `scroll` and `transitionend` events to trigger the
loading of the final image. Scrolling of other elements is not monitored, and will not trigger image
loading.

### Usage

Set the `src` prop to the URL of the image you want loadied lazily, and either specify a placeholder
image URL via the prop `blank-src`, or have a blank placeholder image generated for you by leaving
`blank-src` as `null`.

Specify the width and height of the placeholder via the `blank-width` and `blank-height` props. If
these props are not set, then they will fall back to the `width` and `height` props (which are
applied to the image specified via `src`).

Control the generated blank image color by setting the prop `blank-color`.

Placeholder images (either explicity provided, or dynamicaly generated) should have the same width
and height values, or at least the same aspect ratio, as the `src` image.

Feel free to use the `fluid`, `fluid-grow`, `thumbnail`, and `rounded` props of `<b-img>`.

The `offset` prop specifies the number of pixels that an image needs to be near to the viewport to
trigger it to be shown. The default value is `360`.

The `throttle` prop controls how long (in ms) after a scroll (or `resize`, or `orientationchange`,
or `transitionend`) event happens before checking if the image has come within view (or within
`offset` of view). The default is `100` (ms).

Once an image has come into view and is shown, the event listeners are removed.

**Example usage:**

```html
<template>
  <div>
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(80)" alt="Image 1" />
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(82)" alt="Image 2" />
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(84)" alt="Image 3" />
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(85)" alt="Image 4" />
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(88)" alt="Image 5" />
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(90)" alt="Image 6" />
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(92)" alt="Image 7" />
    <b-img-lazy v-bind="mainProps" :src="getImageUrl(94)" alt="Image 8" />
  </div>
</template>

<script>
  export default {
    data() {
      return {
        mainProps: {
          center: true,
          fluidGrow: true,
          blank: true,
          blankColor: '#bbb',
          width: 600,
          height: 400,
          class: 'my-5'
        }
      }
    },
    methods: {
      getImageUrl(imageId) {
        const { width, height } = this.mainProps
        return `https://picsum.photos/${width}/${height}/?image=${imageId}`
      }
    }
  }
</script>

<!-- b-img-lazy.vue -->
```

### Force show of lazy loaded image

To force the final image to be shown, set the `show` prop to `true`. The `show` prop supports the
Vue `.sync` modifier, and will be updated to `true` when the final image is shown.

<!-- Component reference added automatically from component package.json -->
