gatsbyjs/gatsby · error

[${pluginName}] Specifying both 'jpg' and 'png' formats is n

Error message

[${pluginName}] Specifying both 'jpg' and 'png' formats is not supported. Using 'auto' instead

What it means

Option-validation warning inside generateImageData: the `formats` array contains both `jpg` and `png`, which the pipeline cannot generate jointly. The set is not changed here (unlike gatsby-plugin-sharp's version), so behavior falls back toward 'auto' handling downstream; the warning names the offending plugin via pluginName.

Source

Thrown at packages/gatsby-plugin-image/src/image-utils.ts:268

    sourceMetadata = {
      width,
      height,
      format: sourceMetadata?.format || formatFromFilename(filename) || `auto`,
    }
  } else if (!sourceMetadata.format) {
    sourceMetadata.format = formatFromFilename(filename)
  }

  const formats = new Set<ImageFormat>(args.formats)

  if (formats.size === 0 || formats.has(`auto`) || formats.has(``)) {
    formats.delete(`auto`)
    formats.delete(``)
    formats.add(sourceMetadata.format)
  }

  if (formats.has(`jpg`) && formats.has(`png`)) {
    reporter.warn(
      `[${pluginName}] Specifying both 'jpg' and 'png' formats is not supported. Using 'auto' instead`
    )
    if (sourceMetadata.format === `jpg`) {
      formats.delete(`png`)
    } else {
      formats.delete(`jpg`)
    }
  }

  const imageSizes = calculateImageSizes({ ...args, sourceMetadata })

  const result: IGatsbyImageData["images"] = {
    sources: [],
  }

  let sizes = args.sizes
  if (!sizes) {
    sizes = getSizes(imageSizes.presentationWidth, layout)

View on GitHub (pinned to e85d62f177)

Solutions

1. Specify only one of jpg or png, or omit formats / use "auto"

When it happens

Trigger: Thrown at packages/gatsby-plugin-image/src/image-utils.ts:268 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of gatsbyjs/gatsby@e85d62f177 (2026-08-26). Data as JSON: /api/errors/157b58f93c7bda80. Report an issue: GitHub.