Accessible Media according to BFSG: Making Images, Videos & PDFs Accessible to All

Use the BFSG check to assess whether your offering is covered. This article describes technical checks for images, videos and PDFs.

Accessible Images – Using Alt Texts & Semantic Image Descriptions Correctly

Images must be provided with alternative texts (also: alt tags). These should enable the content to be converted into other formats such as large print, Braille, speech output, symbols, or simplified language, so that visually impaired users can fully grasp the information.

Best Practices for Accessible Images:

Formulate alt texts precisely and descriptively.

Avoid generic filenames like "image1.jpg".

Provide decorative images with empty alt tags (alt="") so screen readers skip them.

Example of an Alt Text:

• Bad: alt="Image"

• Good: alt="Table with sales figures from Q1 to Q4 compared to the previous year"

Accessible Videos – Implementing Subtitles, Transcripts & Audio Descriptions Mandatorily

According to WCAG 2.1, accessible videos are only fully accessible if they provide both visual AND acoustic information. This particularly includes subtitles, audio descriptions, and transcripts. Without these, videos are inaccessible to many people.

According to the dual-channel principle of the Web Content Accessibility Guidelines (WCAG) 2.1, you should ensure that all content is perceivable through two channels (visual and acoustic).

Measures for Accessible Video Content:

Insert automatic or manual subtitles.

Provide transcripts for spoken content.

Insert audio description for blind users.

Example of Accessible Video Design:

• Subtitles: Spoken text is displayed synchronously as text: "Now the expert explains the WCAG criteria."
• Audio Description: "The speaker stands at a flip chart titled 'Accessible Media'."
• Transcript: Complete text version of all audio content for reading.

Accessible PDFs – Ensuring Screen Reader Compatibility & Semantic Structure

PDF documents are often not searchable or compatible with screen readers. These too must be made accessible with text alternatives, correct formatting, and structuring. PDF accessibility requires clean formatting according to DIN EN 301 549 and the PDF/UA standard.

Checklist for Accessible PDF Files:

Use text-based PDF files instead of scanned images.

Insert semantically structured headings (H1-H3) & tags.

Provide alternative texts for images in PDFs.

Define correct reading order & navigation elements (e.g., table of contents, bookmarks).

Example of an Accessible PDF Structure:

• H1-H3 headings for better navigation
• Alternative texts for embedded images: alt="Diagram showing the development of user numbers for accessible web applications"
• Searchable, machine-readable text instead of image PDFs

Checklist: Accessible Media according to BFSG

Images & Graphics

• Meaningful alternative texts (alt texts) for all informative images.

• Provide decorative images with an empty alt attribute (alt="").

• Describe complex graphics (charts, infographics) additionally in the body text.

Videos & Audio

• Provide captions for all videos with spoken content.

• Offer transcripts for audio content.

• Add audio descriptions for videos when visual information is necessary for understanding.

• Use operable media players (keyboard control, volume control).

PDFs & Documents

• Create accessible PDFs (tagged structure, logical reading order).

• Provide alt texts for images in PDFs.

• Specify the document language correctly.

Explore criteria in the WCAG hub. The Accessibility Audit finds machine-evaluable barriers; captions, audio descriptions and PDF reading order need additional manual checks.