The Collaborative International Dictionary of English v.0.48:

Vignette \Vi*gnette"\, v. t.
   To make, as an engraving or a photograph, with a border or
   edge insensibly fading away.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Vignette \Vi*gnette"\ (?; 277), n. [F. vignette, fr. vigne a
   vine. See Vine, and cf. Vinette.]
   1. (Arch.) A running ornament consisting of leaves and
      tendrils, used in Gothic architecture.
      [1913 Webster]

   2. A decorative design, originally representing vine branches
      or tendrils, at the head of a chapter, of a manuscript or
      printed book, or in a similar position; hence, by
      extension, any small picture in a book; hence, also, as
      such pictures are often without a definite bounding line,
      any picture, as an engraving, a photograph, or the like,
      which vanishes gradually at the edge.
      [1913 Webster]

   3. A picture, illustration, or depiction in words, esp. one
      of a small or dainty kind.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

vignette
    n 1: a brief literary description [syn: sketch, vignette]
    2: a photograph whose edges shade off gradually
    3: a small illustrative sketch (as sometimes placed at the
       beginning of chapters in books)

Moby Thesaurus II by Grady Ward, 1.0:

123 Moby Thesaurus words for "vignette":
   Bildungsroman, Gothic novel, aquatint, autolithograph,
   black and white, block, block print, brouillon, cameo, cartoon,
   catalog, cataloging, character, character sketch, characterization,
   charcoal, charcoal drawing, chiaroscuro, chromolithograph,
   color print, comic novel, copperplate, copperplate print, crayon,
   crayon engraving, cut, delineation, depiction, description, design,
   details, detective novel, diagram, dime novel, doodle, draft,
   drawing, dreadful, ebauche, engravement, engraving,
   epistolary novel, erotic novel, esquisse, etching, evocation,
   graph, graphic account, graphotype, historical novel, image,
   imagery, impress, impression, imprint, itemization, limning,
   line drawing, linoleum-block print, lithograph, mezzotint,
   negative, nouvelle, novel, novel of character, novel of ideas,
   novel of incident, novel of manners, novel of sensibility,
   novelette, novella, particularization, pastel, pen-and-ink,
   pencil drawing, penny dreadful, photograph, picaresque novel,
   picture, pornographic novel, portrayal, print, problem novel,
   profile, proletarian novel, propaganda novel, psychological novel,
   regional novel, rendering, rendition, representation, river novel,
   roman, roman a clef, roman-fleuve, rough copy, rough draft,
   rough outline, rubber-block print, satirical novel,
   science-fiction novel, sentimental novel, shilling shocker,
   short story, short-short, silhouette, silver-print drawing,
   sinopia, sketch, sociological novel, specification, storiette,
   stream-of-consciousness novel, study, thesis novel, tracing,
   vivid description, wood engraving, woodblock, woodcut, woodprint,
   word painting, xylograph