In my favourite photo viewing software, FastStone Image Viewer, the only way to add description to the photos is the exif comment field. However, when uploading images to filckr, the title or description fields are not affected by my existing exif comments of the images. I found that if the description is provided in the XMP format, flickr indeed registers and uses them.
I have tried other photo management or viewing software, which supports XMP metadata, but I have not been satisfied with any of them. Therefore, It seems to me, that the best way of keeping my comments when I upload the pictures to flickr is to somehow mirror the exif comments to the XMP description tag. Is there any software which would allow me to do this easily?
As an alternative, the command line tool ExifTool should be able to do this, but as a first time user, I find it hard to make it do what I want it to do. Could someone perhaps give me a hint on how to use the ExifTool to copy the exif comments to XMP description?