XnViewMP - thumbnails - understanding quality/size

[user0]

The Browser tab of XnViewMP may display cached/live thumbnails from different sources (image/embedded thumbnail) with few quality adjustments, depending on the following settings:

1. Thumbnail source
1.1. live/cache

• is Catalog and Thumbnails caching enabled (Settings > Catalog)
  ☑ will be generated from file when folder is opened for the first time (WxH and compression set in Settings > Catalog)
  ☐ will be generated from file each time folder is opened

1.2. image/embedded thumbnail

• is Use embedded thumbnails enabled (Settings > Thumbnails)
  ☑ • does image have embedded thumbnail
         ☑ • is Create from original image if embedded thumbnail is smaller than thumbnail size enabled (Settings > Thumbnails)
                ☑ • is embedded thumb size > thumb rendering size (Browser > View > Thumbnails size)
                       ☑ embedded thumb will be used
                       ☐ will be generated from image
                ☐ will be generated from image
         ☐ will be generated from image
  ☐ will be generated from image

2. Thumbnail rendering
2.1. rendering size (Browser > View > Thumbnails size)

• is image/embedded thumb size > thumb rendering size
  ☑ source will be shrunk to rendered size
  ☐ source will have original size

2.2. rendering quality (Settings > Thumbnails)

• Create high quality thumbnails (bilinear filter)

• Use alpha

• Sharpen

• Use gamma correction

Thumbnails can be rebuild manually

• embedded
  - selected files (Browser > Metadata > EXIF thumbnail > Rebuild)

• live
  - selected files (Browser > View > Rebuild thumbnails)

• cached
  - selected files (Browser > View > Rebuild thumbnails)
  - all files (Settings > Catalog > Rebuild thumbnails)