IF YOU ARE a read-aloud fan, you will be purring like a Cheshire cat over some of the new picture books this spring--purring, sniffing for details, and reaching out to make these books your own.

Ed Young's Up a Tree (Harper & Row, $8.95; ages 3-8) is a cat tale without words, done in soft black-and- white drawings that show every feline twitch, lick, and hiss to perfection. Intriguing variety in page design adds humor and suspense. The next time I am adopted by a cat, I hope it is this one who takes over.

Equally lovable is Carol Newsom's mouse in the exquisite water-color illustrations she has created for An Edward Lear Alphabet (Lothrop, Lee & Shepard, $10; ages 4-8). In blue britches and red galluses, this paunchy little fellow weaves a story into Lear's alphabet poem that begins "A was once an apple-pie . . ." He sleeps in a matchbox, serenades the lion king, sews up the frazzled fist of a rag doll, and provides endless detail to look for and talk about. This is the first children's book illustrated by Carol Newsom and ranks her as an artist to watch and I think to treasure.

Cornelius: A Fable, written and illustrated by veteran Leo Lionni (Pantheon, $9.95; ages 3-7), introduces a crocodile who walks upright and dares to be different despite the scorn of other crocodiles on the river. As in every good fable, there is a moral: it is more fun to stand on your head or hang by your tail than to sneer "So what!" As in every Lionni picture book, the collages are bold, dramatic, and rather impersonal.

"He's just like me!" was the pronouncement of one 4- year-old after meeting Alfie's Feet (Lothrop, Lee & Shepard, $8.50; ages 3-6). Of course! Both love to splash through the biggest puddles, pull on new yellow boots, and splash some more. Both feel comfortable in the cozy clutter of Alfie's home and in the warmth of Mom and Dad. Alfie's exuberance and resourcefulness smile through every drawing. This is the second Alfie book written and illustrated by Shirley Hughes, the 1978 winner of England's prestigious Kate Greenaway Medal.

Every season brings more folk tales for children--old favorites with new illustrations or new tales concocted from old ingredients. Molly Whuppie (Farrar Straus Giroux, $10.95; ages 5-8) is an ancient Celtic story of a gutsy little girl who outwits a giant and wins royal husbands for her two sisters and herself. More than 30 years ago Walter de la Mare retold this tale for children. Now the distinguished artist Errol Le Cain has illustrated the de la Mare version with brilliant full-color paintings that seem as poetic and out-of-this-world as the resonant language of the story.

The Straw Maid (Greenwillow, $9.50; ages 6-9) is also an old, old tale of a heroic little girl who accomplishes the impossible with a flair. Here an ancient tale has been retold in language simple enough for an 8-year-old to read independently. The illustrations are as folksy as an old-time village fair and just as funny. The author-illustrator is Anita Lobel, whose book On Market Street was a Caldecott Honor Book.

Two of the spring books forsake the light-hearted fun and eventual triumph that have been traditional fare for children. Instead each focuses on the way of life of the elderly.

Get Along, Old Scudder (Lothrop, Lee & Shepard, $11; ages 4-8), written and illustrated by Stephen Gammell, is the first-person story of a canny old mountain man who set his traps and looked for beaver in the old West of the early 1800s. Now Old Scudder never was lost, but "one day plumb didn't know what I was at." So he draws a map. With the spare language of the old scout and brilliant pictures done in wet watercolors, Stephen Gammill introduces a spunky old-timer, the breathtaking beauty of the West, and the simple elements of map making.

Miss Maggie by Cynthia Rylant (Dutton, $9.95; all ages) tells of a tobacco-chewing old woman who lives alone in a log cabin, where folks say a black snake hangs from the rafters. When the neighbors' boy is sent with buttermilk and a kettle of beans, her wrinkled brown face cracks into a welcome, but Nat is too scared to linger. This is a touching story of the unspoken friendship that springs up between young and old. Black-and-white illustrations by Thomas Di Grazia emphasize the simplicity of the stark little tale.

Anno's Mysterious Multiplying Jar by Masaichiro Anno and his father Mitsumasa Anno (Philomel, $10.95; ages 4-8) continues the mingling of art and mathematics that the father began in Anno's Counting Book. The new book opens with an exquisite blue-and- white jar of water which begins to ripple and becomes a wide, deep sea. On the sea is an island, and on the island two continents. So the mathematical progression continues with full-color illustrations in the precise Japanese detail for which the father is famous. All lead to an intriguing--and easily understandable--explanation of the important mathematical concept of factorials. This picturebook is deceptively simple entertainment on one level; on another it reveals the remarkable order that underlies the universe.

The Wreck of the Zephyr (Houghton Mifflin, $14.95; ages 6-9) is the fourth book by Chris Van Allsburg, the brilliant young author-artist who won acclaim and innumerable honors and awards for his first three books. All combine the real and the unreal, the bizarre and the beautiful with dramatic imagination and sensitivity. In his latest creation, Van Allsburg tells of the boy who feels his sailboat begin to lift from the water, then glide through the night sky. The lyrical lines and full-color paintings make this an irresistibly beautiful book.