The editable sprites have a four-letter code, a letter key, and one or two rotations. A good example of this is the Imp's first walking frame lumps, labeled TROOA1, TROOA2A8, TROOA3A7, TROOA4A6, and TROOA5. Rotation-wise, if a lump adds another rotation to its name, then the opposite rotation is a mirrored image of the same sprite image. See sprite for a more thorough discussion of Doom's rotation and animation system.
Adding sprites to WADs
Adding sprites with WinTex is relatively simple. First open the WAD, and then select the Sprites section from the menu or by clicking the button with a green character. Sprites can now be loaded from existing bitmap files by choosing Load entry from file from the Edit menu. The dialog gives you a list of template names for some of the most common sprites. For example, it gives SARG@#@# for the demon, in which @#@# must be changed to the code that reflects the desired animation frame rotation.