The Collaborative International Dictionary of English v.0.48:
Picturesque \Pic`tur*esque"\, a. [It. pittoresco: cf. F.
   pittoresque. See Pictorial.]
   Forming, or fitted to form, a good or pleasing picture;
   representing with the clearness or ideal beauty appropriate
   to a picture; expressing that peculiar kind of beauty which
   is agreeable in a picture, natural or artificial; graphic;
   vivid; as, a picturesque scene or attitude; picturesque
   language.
   [1913 Webster]
         What is picturesque as placed in relation to the
         beautiful and the sublime? It is . . . the
         characteristic pushed into a sensible excess. --De
   Quincey.
   [1913 Webster] -- Pic`tur*esque"ly, adv. --
   Pic`tur*esque"ness, n.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
colorful \colorful\ adj.
   1. having striking color. Opposite of colorless.
   Note: [Narrower terms: changeable, chatoyant, iridescent,
         shot; deep, rich; flaming; fluorescent, glowing;
         prismatic; psychedelic; red, ruddy, flushed,
         empurpled]
   Syn: colourful.
        [WordNet 1.5]
   2. striking in variety and interest. Opposite of colorless
      or dull. [Narrower terms: brave, fine, gay, glorious;
      flamboyant, resplendent, unrestrained; flashy, gaudy,
      jazzy, showy, snazzy, sporty; picturesque]
      [WordNet 1.5]
   3. having color or a certain color; not black, white or grey;
      as, colored crepe paper. Opposite of colorless and
      monochrome.
   Note: [Narrower terms: tinted; touched, tinged; amber,
         brownish-yellow, yellow-brown; amethyst; auburn,
         reddish-brown; aureate, gilded, gilt, gold, golden;
         azure, cerulean, sky-blue, bright blue; bicolor,
         bicolour, bicolored, bicoloured, bichrome; blue,
         bluish, light-blue, dark-blue; blushful,
         blush-colored, rosy; bottle-green; bronze, bronzy;
         brown, brownish, dark-brown; buff; canary,
         canary-yellow; caramel, caramel brown; carnation;
         chartreuse; chestnut; dun; earth-colored,
         earthlike; fuscous; green, greenish, light-green,
         dark-green; jade, jade-green; khaki; lavender,
         lilac; mauve; moss green, mosstone; motley,
         multicolor, culticolour, multicolored, multicoloured,
         painted, particolored, particoloured, piebald, pied,
         varicolored, varicoloured; mousy, mouse-colored;
         ocher, ochre; olive-brown; olive-drab; olive;
         orange, orangish; peacock-blue; pink, pinkish;
         purple, violet, purplish; red, blood-red, carmine,
         cerise, cherry, cherry-red, crimson, ruby, ruby-red,
         scarlet; red, reddish; rose, roseate; rose-red;
         rust, rusty, rust-colored; snuff, snuff-brown,
         snuff-color, snuff-colour, snuff-colored,
         snuff-coloured, mummy-brown, chukker-brown; sorrel,
         brownish-orange; stone, stone-gray; straw-color,
         straw-colored, straw-coloured; tan; tangerine;
         tawny; ultramarine; umber; vermilion,
         vermillion, cinibar, Chinese-red; yellow, yellowish;
         yellow-green; avocado; bay; beige; blae
         bluish-black or gray-blue); coral; creamy; cress
         green, cresson, watercress; hazel; honey,
         honey-colored; hued(postnominal); magenta;
         maroon; pea-green; russet; sage, sage-green;
         sea-green] [Also See: chromatic, colored, dark,
         light.]
   Syn: colored, coloured, in color(predicate).
        [WordNet 1.5]
Moby Thesaurus II by Grady Ward, 1.0:
59 Moby Thesaurus words for "picturesque":
   arabesque, attractive, baroque, busy, charming, chichi, colorful,
   delightful, elaborate, elegant, fancy, fetching, fine, flamboyant,
   florid, flowery, freehand, frilly, fussy, graphic, high-wrought,
   idyllic, interesting, intriguing, labored, lovely, luxuriant,
   luxurious, monochrome, moresque, original, ornate, ostentatious,
   overelaborate, overelegant, overlabored, overworked, overwrought,
   painty, pastose, photographic, pictorial, picturable, pictural,
   pleasing, polychrome, pretty, pretty-pretty, quaint, realistic,
   rich, rococo, scenic, scenographic, scumbled, striking, unique,
   unusual, vivid