The default theme build process will automatically embed images using data URLs if they are smaller than 10000 bytes. This is a feature of the url-loader used in our Webpack configuration to optimize the loading time of the website.

You can change the threshold for embedding images if this does not fit your needs by adding a build config to either the Section 6.2, “Theme Config” (preferred) or the coremedia entry of your theme's package.json:

{
  ...
  "buildConfig": {
    "imageEmbedThreshold": 20000
  }
  ...
}

The example will set the threshold to 20000 bytes. Setting the value to 0 means that all images will be embedded regardless of their size (not recommended), -1 will disable the functionality completely so images will not be embedded using a data URL.