There is a subtle difference between the Bioware and Skyrim dds formats.
Now that Photoshop no longer supports tga or dds, I recommend XnConvert, a very general tool for reformating images.
XnConvert will convert Skyrim dds to almost any format you like (e.g. jpg, tga).
I also use it to convert tga to formats Photoshop can read (and vice-versa).
To convert from Skyrim dds to Bioware dds, use XnConvert to reformat as tga, then use the Bioware tool:
http://neverwinterva...dds-converte...