Reply To: Beginners Guide to creating a Rico skin mod
+1 for paint.net . It’s support of dds is good. But if you plan to edit normals and *, nvidia texture tools are extremely good. The ultra-high level is the quixel suite, but that’s not free. (but oh god ! that’s pure awesomeness).
There’s also a gimp plugin that support dds, but it may refuse to open some of the dds file or save correctly. (I don’t remember the last update of the dds plugin, but if I recall correctly, that’s some years that it hasn’t been updated).