Node Preview V1.20

Features

For each node, a preview thumbnail is rendered
On edits, all affected nodes are automatically updated
Previews are rendered in a background process to keep the Blender interface fluid and responsive
No changes are made to the .blend, others without the addon can still open your scenes without problems
High-resolution displays supported (works with Blender's resolution scale feature)

Caveats

To show previews for packed images, the .blend file has to be saved to disk first, because they are loaded through linking from the .blend file
Thumbnails of image sequences are not updated when changing frames
IES nodes are currently not supported