Enable Jellyfin chapter images without unexpectedly expanding scan work

The useful distinctions

• Chapter images are distinct from chapter markers.
• Extraction is enabled per video library.
• The during-scan option moves extraction work into Scan Media Library instead of the separate Extract Chapter Images task.
• Libraries Metadata includes a seconds-based dummy-chapter interval, with zero disabling dummy chapters.

Separate navigation from pictures

A timeline marker and an image preview are related but different features. Decide which experience you need before changing extraction settings. If users can already navigate chapters, the missing pictures do not necessarily mean the chapter data is absent. This distinction prevents a cosmetic preview request from becoming an unnecessary effort to rewrite the original media or rebuild an entire catalogue.

Budget work where it runs

A small library makes the effect of extraction easier to observe. Record whether ordinary scanning remains responsive and whether previews appear for a few known chapter positions. The example keeps extraction outside the scan so the administrator can evaluate each job separately. It is a scheduling choice to assess, not a promise about completion time or the processing capacity of a particular server.

Avoid accidental density

For files without chapters, a chosen interval can create a very different number of preview positions in a short clip and a long recording. Work out that difference before selecting a dense interval for every video. A preview should help someone recognize a location, so larger image dimensions or more positions are not automatically better. Keep a written pilot result and revisit the settings with representative short and long items.

A focused way to proceed

1. Open an existing video library’s three-dot menu and its Chapter Images settings.
2. Enable extraction for a small pilot library.
3. Choose whether extraction belongs inside scans or in its separate task.
4. In Libraries, Metadata review interval and preview resolution before expanding the pilot.

Worked example · synthetic

Pilot: Workshop Clips video library
Chapter image extraction: enabled
During library scan: disabled for initial comparison
Dummy chapter interval: 0 while assessing existing chapters
Review: one short clip and one long recording

Read the comparison

Chapter markers without pictures can be expected when image extraction is disabled or unfinished.

When to stop or ask for help

If extraction fails, collect the relevant task and media information rather than only a timeline screenshot.