Are you referring to texture maps for models?  IIRC, saving for the web only conditions the files for computer viewing, it does not take into account any printing a user may undertake after rendering a scene.  Saving as a straight jpeg directly from PS should suffice.  You really would not want to sacrifice pixel deletion to compress your file further.  Also, PSD or PNG format are rather large files.  They are better because of their lossless nature but add quite of overhead to storage.