gatsby-remark-images-uploadcare

Processes images in markdown with Uploadcare.

In the processing, it makes images responsive by:

• Uploading local images to Uploadcare CDN and generating multiple versions of images at different widths, format and quality and sets the srcset and sizes of the img element so regardless of the width of the device, the correct image is downloaded.
• Adding an elastic container to hold the size of the image while it loads to avoid layout jumps.
• Using the "blur up" technique popularized by Medium and Facebook where a small 20px wide version of the image is shown as a placeholder until the actual image is downloaded.
• Allow to set custom image transformation for all images and for each image.

Install

npm install gatsby-remark-images-uploadcare

How to use

Create account https://app.uploadcare.com/accounts/login/ and generate secretKey. 3000 uploads, 30 GB traffic and 3 GB storage - FREE. Pass pubkey and secretKey to plugin options. https://uploadcare.com/docs/start/settings/#keys

// In your gatsby-config.js
plugins: [
  {
    resolve: `gatsby-transformer-remark`,
    options: {
      plugins: [
        {
          resolve: `gatsby-remark-images-uploadcare`,
          options: {
            pubkey: process.env.GATSBY_UPLOADCARE_PUBKEY,
            secretKey: process.env.UPLOADCARE_SECRET_KEY,
            // It's important to specify the maxWidth (in pixels) of
            // the content container as this plugin uses this as the
            // base for generating different widths of each image.
            maxWidth: 768,
          },
        },
      ],
    },
  },
]

Usage in Markdown

You can reference an image using the relative path, where that path is relative to the location of the Markdown file you're typing in.

![Alt text here](./image.jpg)

By default, the text Alt text here will be used as the alt attribute of the generated img tag. If an empty alt attribute like alt="" is wished, a reserved keyword GATSBY_EMPTY_ALT can be used.

![GATSBY_EMPTY_ALT](./image.png)

Options

Name	Default	Description
maxWidth	650	The maxWidth in pixels of the div where the markdown will be displayed. This value is used when deciding what the width of the various responsive thumbnails should be.
imageOperations	{ quality: 'smart', format: 'auto' }	Set the base image operations for all images. https://uploadcare.com/docs/transformations/image/
linkImagesToOriginal	true	Add a link to each image to the original image. Sometimes people want to see a full-sized version of an image e.g. to see extra detail on a part of the image and this is a convenient and common pattern for enabling this. Set this option to false to disable this behavior.
showCaptions	false	Add a caption to each image with the contents of the title attribute, when this is not empty. If the title attribute is empty but the alt attribute is not, it will be used instead. Set this option to true to enable this behavior. You can also pass an array instead to specify which value should be used for the caption — for example, passing ['alt', 'title'] would use the alt attribute first, and then the title. When this is set to true it is the same as passing ['title', 'alt']. If you just want to use the title (and omit captions for images that have alt attributes but no title), pass ['title'].
markdownCaptions	false	Parse the caption as markdown instead of raw text. Ignored if showCaptions is false.
wrapperStyle	``	Add custom styles to the div wrapping the responsive images. Use the syntax for the style attribute e.g. margin-bottom:10px; background: red;.
backgroundColor	white	Set the background color of the image to match the background image of your design. Note: - set this option to transparent for a transparent image background. - set this option to none to completely remove the image background.
loading	lazy	Set the browser's native lazy loading attribute. One of lazy, eager or auto.
decoding	async	Set the browser's native decoding attribute. One of async, sync or auto.
disableBgImage	false	Remove background image and its' inline style. Useful to prevent Stylesheet too long error on AMP.
srcSetBreakpoints		By default gatsby generates 0.25x, 0.5x, 1x, 1.5x, 2x, and 3x sizes of thumbnails. If you want more control over which sizes are output you can use the srcSetBreakpoints parameter. For example, if you want images that are 200, 340, 520, and 890 wide you can add srcSetBreakpoints: [ 200, 340, 520, 890 ] as a parameter. You will also get maxWidth as a breakpoint (which is 650 by default), so you will actually get [ 200, 340, 520, 650, 890 ] as breakpoints.

Image operations for all images

{
  resolve: `gatsby-remark-images-uploadcare`,
  options: {
    maxWidth: 800,
    imageOperations: {
      quality: 'lightest',
      progressive: 'yes',
      sharp: '20'
    }
  },
}

Image operations for single image, will be override base imageOperations from plugin options.

    ![Alt text here](./image.jpg?blur=50&contrast=10)

Prevent image processing by Uploadcare plugin, by this option image will not be process Uploadcare and copy as-is to public folder.

    ![Alt text here](./image.jpg?noProcess)

gif2video converts animated image files, such as GIF, WebP and HEIC to video and transforms them on the fly. Video files are much smaller than GIFs. https://uploadcare.com/docs/transformations/gif-to-video/

    ![Alt text here](./image.giff)

This plugin will not support GIFs or SVGs. If you would like to render these file types with the image markdown syntax, use the gatsby-remark-copy-linked-files plugin. Do note with this it will load in the images, but won't use the features of [Sharp][5] such as the elastic container or the blur-up enhancements.