Doom Hi-Res Graphics Inquiry

[mac53]

First, I'd like thank Joe Foster for his offer and following through with it... definetely some good material. Now, this brings me back to inquire about if any member has knowledge of the construction of Hi-Res graphics. I'm interested in taking the Doom 2 sprites textures and converting them into 4x High-Resolution. Expanding graphics to 4x their size is one thing, but actually turning them into beautiful Hi-Res's is another. If anyone with this knowledge wouldn't mind advising as to what software needed and the process in getting this accomplished, I would appreciate their help.

Thank you...