ThumbnailDisplayFilter specifies a filter to apply when an image (thumbnail) need to be resized for display. Filters improve the quality of the thumbnail, but can slow down the application.
A value of rfNone provides no quality enhancement. Filters such as rfLanczos3 provide excellent quality, but are slower. A typical value is rfFastLinear which improves quality with negligible speed impact.
Note: ◼Unlike ThumbnailResampleFilter, ThumbnailDisplayFilter is used every time the image needs to be displayed ◼For black/white images rfFastLinear is always used.