31 U.S.C. § 1355

(a) No funds appropriated or otherwise made available to the Federal Government may be used to pay for the painting of a portrait of an officer or employee of the Federal Government, including the President, the Vice President, a Member of Congress, the head of an executive agency, or the head of an office of the legislative branch. (b) In this section— (1) the term “executive agency” has the meaning given the term in section 133 of title 41 ; and (2) the term “Member of Congress” includes a Delegate or Resident Commissioner to Congress.