Resized files not resized
Thanks for your feature request, thats a good idea. There will be a new release, most probably end of december, which also implements your feature request.
Flexxi can resize jpg, gif and png images, all other formats (e.g. .dds) are treated as "other files" and just copied (or ignored; see settings) to the target location. Since the Bitmap Class of C# (used for resizing) does not support .dds, there are also no plans to extend the supported file formats to *.dds.