ocrmypdf/OCRmyPDF · error · DpiError

Input file is an image, but has no resolution (DPI) in its m

Error message

Input file is an image, but has no resolution (DPI) in its metadata.  Estimate the resolution at which the image was scanned and specify it using --image-dpi.

What it means

Raised when an image input file has no DPI metadata at all. Without resolution info ocrmypdf cannot compute page dimensions for the output PDF, so it requires --image-dpi.

Source

Thrown at src/ocrmypdf/_pipeline.py:117

            log.error("Input file is a file: %s", input_file)
        if input_file.stat().st_size == 0:
            log.error("Input file is empty: %s", input_file)
        raise UnsupportedImageFormatError() from e

    with im:
        log.info("Input file is an image")
        if 'dpi' in im.info:
            if im.info['dpi'] <= (96, 96) and not options.image_dpi:
                log.info("Image size: (%d, %d)", *im.size)
                log.info("Image resolution: (%d, %d)", *im.info['dpi'])
                raise DpiError(
                    "Input file is an image, but the resolution (DPI) is "
                    "not credible.  Estimate the resolution at which the "
                    "image was scanned and specify it using --image-dpi."
                )
        elif not options.image_dpi:
            log.info("Image size: (%d, %d)", *im.size)
            raise DpiError(
                "Input file is an image, but has no resolution (DPI) "
                "in its metadata.  Estimate the resolution at which "
                "image was scanned and specify it using --image-dpi."
            )

        if im.mode in ('RGBA', 'LA'):
            raise UnsupportedImageFormatError(
                "The input image has an alpha channel. Remove the alpha channel first."
            )

        if 'iccprofile' not in im.info:
            if im.mode == 'RGB':
                log.info("Input image has no ICC profile, assuming sRGB")
            elif im.mode == 'CMYK':
                raise UnsupportedImageFormatError(
                    "Input CMYK image has no ICC profile, not usable"
                )

View on GitHub (pinned to 5074a0b0e1)

Solutions

1. Pass --image-dpi with the estimated scan resolution (commonly 300)
2. Embed DPI metadata in the image before running (Pillow: img.save(..., dpi=(300,300)))
3. Convert to PDF yourself with img2pdf specifying the layout

Example fix

# before
ocrmypdf photo.png out.pdf
# after
ocrmypdf --image-dpi 300 photo.png out.pdf

from PIL import Image
with Image.open(src) as im:
    if 'dpi' not in im.info and not image_dpi:
        image_dpi = 300

When it happens

Trigger: Passing an image with no 'dpi' key in its Pillow info dict and no --image-dpi option; raised in triage_image_file.

Common situations: PNG files (which often omit DPI), downloaded images, images processed by tools that strip metadata.

Related errors

• Input file is an image, but the resolution (DPI) is not cred
• --redo-ocr (or --mode redo) is not currently compatible with
• Since you specified `--output-type none`, the output file {s
• The input image has an alpha channel. Remove the alpha chann
• Input CMYK image has no ICC profile, not usable

AI-assisted analysis of ocrmypdf/OCRmyPDF@5074a0b0e1 (2026-08-27). Data as JSON: /api/errors/dbd633f337fcef55. Report an issue: GitHub.