"It's a great image: the shy, sensitive guy with his guitar slung over his shoulder, wind feathering his hair as he strolls barefoot through the great outdoors, searching for the words and the tune that will capture the feeling in his heart. You can see that image on record jackets, as a TV character, in shampoo ads - for almost two decades, the media have ingrained it into every consumer.

Right now that image bears little resemblance to reality. The guy on the record cover has a backup band, a producer, perhaps an arranger as well. Look closely at his guitar and you'll see exactly where it plugs in. The few surviving tolkies are getting harder to find then a nickel pinball machine in a city full of Pong games. To travel in the pop mainstream, a song usually needs a simple musical idea, a universally appealing (i.e., vague and general) lyric and a full sounding arrangement tailored for radio. Gladly or not, most songwriters are willing to reshape their singular visions accordingly.

Kenny Loggins is happy to share his visions. As cofounder of Loggins & Messina, he submitted his songs to Jim Messina's country inclinations at first; eventually, L&M assembled a strong, electric band that added creative variations to Loggin's winsome, hit bound songs. For both of his post L&M "solo" albums, Loggins has enlisted producer Bob James, who has a background in slick pop jazz arranging. Loggins' songs on his new LP "Nightwatch" (Columbia JC 35387) are still simple and catchy, but he's enlisted various colyricists, perhaps to keep from getting too personal (Sample: "Everywhere we are/You and I were meant to be/Forever and ever"); his voice is an warmly ingenuous as ever.

This time, though, Loggins has given James too much authority. James is up-to-the-minute - he usese electronic sounds, harmonics on the electric bass, intricate strings and horns - but his arranging details are so obsessively polished they distract from the songs they embellish. In the ballads, James is continually showing off his spacy echo effects; in what ought to be rockers, James sets up rhythm 'n' blues grooves that are too complacent. Each instrument sounds gorgeous, but the total effect is misplaced, like a Mercedes sedan entered in a drag race. James lends undue gravity to songs that are, at best, light entertainment.

Harry Chapin is a lot closer to the folks singers of bygone days. Chapin not only writes songs he can strum by himself if necessary, but also shows a sincere interest in children and plays benefits to fight hunger. His heart seems to be in the right place, and I wish I could enjoy his music. On "Living Room Suite" (Elektra 6E-142), Chapin usually avoids the braying vocals and overbearing backup that made songs like "Cat's in the Cradle" and "WORLD" so obnoxious. Chuck Plotkin's production is gentle, and Chapin makes an effort to sing quietly.

Unfortunately, Chapin has a lot of old folkies' bad habits: little or no interest in rhythm, a sense of self-right-eousness and lyrics so banal they make me cringe. ("I know about finders keepers/And how losers are the weepers"). His personae are unintentionally grating; for instance, in "If You Want to Feel" he sounds like a dirty old man cruising a singles bar; "In the years of your youth you can't be fireproof/You know you got to get burned." Even when I agree with Chapin, he's hard to take. "Flowers Are Red" a song about schools stifling creativity, and "Why Do Little Girls." decrying cultural sterotyping, are both embarrassingly overwritten with strong overtones of harangue. Chapin would be better off if he trusted his listeners to reach their own conclusions.

Because he doesn't try to impress or preach, and because he sings in a brotherly voice that admits to sorrow as well as strength, Jesse Winchester is far more believable that Loggins or Chapin. He's kind, courtly, almost an old-fashioned gentleman asking your indulgence for "A Touch on the Rainy Side" (Warner Bros. BRK 6884). In "A Showman's Life," dealing with life on the road. Winchester worries about his "lonely wife" and rues the prospect of "good times" and "money" that got him out in the first place: he's too mature to really enjoy them. As he tries a "little Glass of Wine," he knows he's drinking "a comfort to the fool," and makes no pretensions to importance.

Beneath Winchester's adult values lies an almost Biblical sense of duty. Songs such as the gospel-like "I'm Looking for a Miracle" reveal him as an agnostic, and earlier songs like "Isn't It So" have a pagan sensibility, but even Winchester's tales of daily life are ennobled by a touch of the mystic. At the same time he's rockin' down the highway in "High Ball," he's thinking."I'm not long for this olw world," and it keeps him humble.

Winchester's conscience forced him to emigrate to Canada in 1967 to escape the draft, and he only returned to the United States (as a visitor) last year thanks to a presidential pardon. "A Touch on the Rainy Side," his sixth LP is thus the first he's recorded in the U.S., and he chose to work in Nashville with producer Norbert Putnam. The alhum is resolutely noncountry - Jesse's a Memphis native, with a talent for rhytm-'n'-blues ballads - and the settings are as measured as the songs. Like its predecessor. "Nothin' But a Breeze," the new album goes easy on the soul-searching parables Winchester's been noted for, in favor of ballads and love songs. Winchester says the shift in emphasis is the result of his life "lightening up," not a bid for commerciality, and I tend to believe him, although I do recommend his older albums highly.

Winchester still writes quiet, intospective songs, like a thousand other guys with ruitars. His saving graces are his moral sense and his abiding humility - two hallmarks of a folk heart in a pop universe.