CUPERTINO, California (Reuters) - Apple Inc. unveiled a line of slimmer desktop computers on Tuesday in a long-expected update of its iMac brand, positioning it for the back-to-school and holiday shopping seasons.

The new iMacs, which will sport thinner aluminum casings, have displays measuring 20 inches and 24 inches and will cost $1,199 to $1,799, depending on their configurations, said Apple Chief Executive Steve Jobs at a media event at Apple's headquarters in Cupertino, California.

The cost of the 24-inch iMac has been dropped by $200, and Apple has eliminated the 17-inch iMac computer, Jobs said.

The last update to the iMac line was in September 2006, when Apple introduced a model with a 24-inch screen -- its largest -- and said the entire model line would be powered by Intel chips instead of ones from International Business Machines Corp. .

Apple recently launched the iPhone mobile device in a bid to build a third major product line alongside its Macintosh computers and iPod media players, but desktop and laptop sales still account for the bulk of its revenue.

In its third quarter, Apple sold 634,000 desktops for revenue of $956 million, accounting for about 18 percent of total revenue.

(Writing by Duncan Martell, Reporting by Scott Hillis)
© Copyright 2007 Reuters.