Images not available in markdown from URL

[FaFre]

Bug

It seems like it is not possible to capture images from URL with any image-export-mode. The error assumes the usage of the PDF pipeline that is not the case, because the input is HTML.

# Stuttgart

aus Wikipedia, der freien Enzyklopädie

<!-- 🖼️❌ Image not available. Please use `PdfPipelineOptions(generate_picture_images=True)` -->

Der Titel dieses Artikels ist mehrdeutig. Weitere Bedeutungen sind unter  aufgeführt.

Das für Öffentlichkeitsarbeit verwendete Logo der Landeshauptstadt Stuttgart

<!-- 🖼️❌ Image not available. Please use `PdfPipelineOptions(generate_picture_images=True)` -->

Stuttgarter Schloßplatz am Morgen

<!-- 🖼️❌ Image not available. Please use `PdfPipelineOptions(generate_picture_images=True)` -->

Arkadenhof im Alten Schloss

<!-- 🖼️❌ Image not available. Please use `PdfPipelineOptions(generate_picture_images=True)` -->

Typisch hügeliges Stadtbild am Stuttgarter Talkessel: Blick auf die Karlshöhe

<!-- 🖼️❌ Image not available. Please use `PdfPipelineOptions(generate_picture_images=True)` -->

Steps to reproduce

docling https://de.wikipedia.org/wiki/Stuttgart --image-export-mode embedded

Docling version

Docling version: 2.27.0
Docling Core version: 2.23.3
Docling IBM Models version: 3.4.1
Docling Parse version: 4.0.0
Python: cpython-313 (3.13.2)
Platform: Linux-6.12.19-1-lts-x86_64-with-glibc2.41

Python version

Python 3.13.2

[PeterStaar-IBM]

@FaFre Yes, this is because the backend is not yet downloading the images (or registering the urls from the html). The error message here is somewhat misleading. We should,

1. update the backend here:
   • https://github.com/docling-project/docling/blob/main/docling/backend/html_backend.py#L509
   • https://github.com/docling-project/docling/blob/main/docling/backend/html_backend.py#L538
2. update the error-message in the markdown output