Troubleshooting verification failure - Figure tag missing BBox attributes (Desktop and Advanced Editor)

Issue

When validating a PDF for PDF/UA compliance, you may receive a failure indicating that one or more images do not have Bounding Box (BBox) attributes or that the existing BBox values are incorrect.

A Bounding Box defines the exact position and dimensions of an object on a page, such as an image, table, or link. These attributes allow assistive technologies and PDF processors to accurately identify the location and size of tagged page elements.

This issue can be resolved quickly using the Fix Wizard in CommonLook PDF.

Symptom 

The PDF/UA Accessibility Checker reports a failure indicating that an image is missing a Bounding Box (BBox) attribute.

1.  The Accessibility Results pane displays an error similar to:

• Image BBox attribute missing
• Image Bounding Box not set
• Image BBox incorrectly set

2.  One or more images appear in the list of failed accessibility checks.

Causes

This issue typically occurs when:

• An image was added or modified without updating its Bounding Box attributes.
• The Bounding Box values became invalid during document editing or conversion.
• A third-party application generated the PDF without properly calculating the BBox values.

Because the Bounding Box identifies an object's position and size, missing or incorrect values can prevent PDF/UA conformance.

Affected Users

• Screen reader users, whose assistive technologies rely on properly tagged document structures.
• Users of other assistive technologies that interpret tagged PDF content.

Accessibility Guidelines

PDF/UA-1) – Tagged objects such as figures require appropriate attributes, including valid Bounding Box (BBox) information where required for conformance.

Resolution Steps

1. Locate the Failure

Run the PDF/UA Accessibility Checker and locate the image BBox failure in the Results pane.

2. Open the Fix Wizard

Depending on the editor you are using:

Desktop Editor

• Double-click the failed result, or
• Right-click the failure and select Fix.

Advanced Editor

• Select the three-dot (⋮) menu next to the failure.
• Choose Fix.

3. Calculate the Bounding Box

The Fix Wizard provides a single option:

• Calculate and set the BBox attribute

Leave this option selected.

4. Apply the Fix

Select Finish to calculate and assign the correct Bounding Box values.

5. Apply the Fix to Multiple Images (Optional)

If multiple images have the same issue:

Before selecting Finish, enable:

Apply fix to all similar issues - This automatically updates every image with the same validation failure, eliminating the need to fix each one individually.

6. Save the Document

Save the document after the Fix Wizard completes.

Verification

The issue has been successfully resolved when:

• The Image BBox failure no longer appears in the Accessibility Results.
• The image passes PDF/UA validation.
• No additional Bounding Box errors are reported after rerunning the accessibility checker.