---
title: When to Use Which
url: https://docs.kaltura.com/docs/rich-media-cms-apis/content-management/thumbnail-when-to-use-which
---

## When to Use Which


| Need | Use | Why |
|------|-----|-----|
| Display thumbnails in a UI at various sizes | **Dynamic Thumbnail URL** | CDN-cached, no stored assets, infinite size combinations |
| Hover preview / timeline scrubber | **Dynamic Thumbnail URL** with `vid_slices` | Single HTTP request for all preview frames |
| Custom-designed marketing thumbnail | **thumbAsset.add + setContent** | Persistent, editable, independent of video content |
| Capture and save a specific video frame | **thumbAsset.generate** | Stored permanently, can be set as default |
| Auto-generate thumbnails on upload | **thumbParams** + conversion profile | Zero-touch automation |
| Change which thumbnail shows by default | **thumbAsset.setAsDefault** | Controls the entry's `thumbnailUrl` property |
| Extract a frame without storing it | **Dynamic Thumbnail URL** with `vid_sec` | Transient, CDN-cached, no asset created |