A PICTURE CAN sell a thousand words. Certainly this is true of holiday gift books for children in which stunning artwork is often required to save some unremarkable narrative. Fortunately, this season, there are several exceptional volumes whose texts are not merely excuses for the work of marvelous artists.

It is about time that Nancy Willard, the author of Sailing to Cythera, composed a book of verses for children, and A Visit to William Blake's Inn: Poems for Innocent and Experienced Travelers (Harcourt Brace Jovanovich, $10.95. All ages) is all one would expect from this distinguished poet. The title should not suggest that this picture book is merely a chronicle of the mystical English poet-painter. Instead, it is a collection of lyrical nonsense poems inspired by a reading of his Songs of Innocence when Willard was a little girl. These elegant, crisp and clean rhymes describe an enchanted wayside inn where dragons bake the morning bread and a man in a marmalade hat leads the Tyger and the King of the Cats in a dance. Surely Edward Lear and Lewis Carroll could not have asked for a better place to spend a pleasant night than here.

Like Willard with Blake's poetry, illustrators Alice and Martin Provensen have not tried to imitate the mystic's art. Instead, their master here is obviously Edward Hicks, the American primitive painter. They have produced one of the most seductive picture books of recent years, each elegant spread touched with quaint charm and comfort; and despite their dazzling colors and deft drawing, their pictures never overpower but rather complement their collaborator's fancies. Here the art is as inviting as the verses.

William Blake's Inn might have been a welcome stop for the traveling players of Irene Haas' The Little Moon Theater (Atheneum/Margaret K. McElderry, $9.95. Ages 5-9). Reminiscent of both Maurice Sendak's Higglety Pigglety Pop! and Tomie de Paola's When Everyone Was Fast Asleep, the new picture book follows the harmless adventures of Jo Jo, Jip, and Nicolette on their journey from season to season in a brightly painted caravan. While performing from town to town, they befriend those in distress; and in the end, they are rewarded by having a wish granted by a tardy fairy godmother. The story may not seem like much, but it is enlivened by a suite of haunting images in watercolor. Few other children's book illustrators understand color so brilliantly as Haas in her warm and cozy designs. True, this artist is less adroit with words than with her brush. However, like A Visit to William Blake's Inn, The Little Moon Theater is clearly intended not so much to record dreams as to inspire them.

Margot Tomes is perhaps the only major children's book artist who has never had a major project. Obviously her new edition of Frances Hodgson Burnett's Sara Crewe, or What Happened at Miss Minchin's (Putnam, $9.95. Ages 9-up) is an attempt to correct this negligence. In pictures in full color and in black and white, Tomes appropriately (and often wittily) interprets the famous story which was later expanded into the even better-known novel The Little Princess.

Although introducing the conventional conflict between an abused heroine and her cruel guardian, Burnett was as hard on little Sara as she was on stupid Miss Minchin. Likewise, Tomes shows this odd child as the misfit she is. Sara Crewe is not the ideal heroine. The artist presents the story as if it were being seen through the poor creature's eyes: Miss Minchin is thus transformed into an ogress; the doll, given Sara by her dear departed father, has an almost otherworldly presence; and Sara herself, in her youthful arrogance, always dominates the action. Tomes is also original in her atmospheres, in her depicting the interminable coldness of London winters and the overstuffed ugliness of Victorian parlors. Neither Burnett nor Tomes in this new Sara Crewe is a sentimentalist.

With the classic Savoy operetta a long-running hit on Broadway, it is not surprising that a picture book version of The Pirates of Penzance (Random House, $8.95. All ages) has just been published. Can an easy-to- read Nicholas Nickleby be far behind? Perhaps much of the sophisticated silliness of W.S. Gilbert's plot is lost on most children. Nevertheless, Ward Botsford has written a lively adaption of the original libretto, larding it with snatches of the lyrics from the play's most famous numbers; and cartoonist Edward Sorel has matched this sympathetic retelling with some funny and exuberant illustrations. Yes, perhaps Sorel's Frederick is a bit too swish for Gilbert's swashbuckler; he is certainly prettier even than fair Mabel. When the children get older, they may also want to dip into Gilbert Without Sullivan (Viking/Studio, $14.95. All ages) a collection of the full libretti for H.M.S. Pinafore, The Pirates of Penzance, The Mikado, and The Gondoliers, enhanced with elegant line drawings in mauve by L.B. Lubin. Certainly their parents who have just taken in the Broadway show will want to pick up both of these handsome volumes.

Tom Seidmann-Freud, in her sad short life, wrote and illustrated several of the most endearing of modern German picture books. A niece of the father of psychoanalysis, this young artist employed the latest theories of child psychology in her experiments with the form which she then tested on her own little girl. However, distressed with financial worries during the Depression, her husband committed suicide; and bereft by his death, she reportedly took her own life soon after, in 1930, when she was only 37. Then, in 1937, because she had been non-Aryan, the Nazis banned her children's books.

Happily, one of her cleverest efforts The Magic Boat (Greenwillow, $5.95. All ages) has finally been issued in English. But what in this simple mechanical picture book could have offended the Nazis? By pulling a tab, the reader can follow a household through its day; by turning a wheel, a hare can race a hedgehog and the characters in the magic boat and on the bridge above change from one to another; by looking through a card of magic windows, one can "read" various sequences of related objects. Each of this book's devices was designed to involve the young reader in the storytelling.

Economic considerations have forced this edition to be less elaborate than the original German one; also, the pictures have had to be redrawn, and the text is not an accurate translation. But no matter. This Magic Boat still contains many adventures as enchanting as any encountered at William Blake's Inn, the Little Moon Theater, Miss Minchin's or Penzance.