XnView Software

when renaming files or moving, the thumbnails are generated again, which is very silly as possible just to move the data in the database of thumbnails (cache), So this causes a re-scan of files to create thumbnails.

For the background of the thumbnails transparent images to use color settings of the background transparency.

If you have enabled caching of the thumbnails but the files are moved and enabled display table. it is not displayed in the table of file properties (e.g. size) , color coding of file types.

rename/move in XnView?

of course in XnView, also forgot to write about copying.

and it is possible to add an even stronger level of compression of thumbnails.

The rate of optimization of the cache is very low.
Perhaps there is also something that can be optimized. For example, just quick check by file name (whether it exists in a folder or not).

If you have enabled caching of the thumbnails but the files are moved and enabled display table. it is not displayed in the table of file properties (e.g. size) , color coding of file types

File data does not appear until image thumbnails are created.