He pronounced it ‘jif,’ like the peanut butter brand

The cause was covid-19, said his wife, Kathaleen Wilhite.

Mr. Wilhite was working at CompuServe, the nation’s first big online service provider, when he created the Graphics Interchange Format in 1987, a few years before the advent of the World Wide Web. The company’s chief technical officer, Alexander “Sandy” Trevor, had enlisted him to make an image file format that used lossless compression and could work across an array of computer systems, enabling users to share photos, stock charts, weather maps and other files across the slow communication lines of the dial-up age, regardless of whether they were using an Apple, Atari, Commodore, IBM or Tandy computer.

Within a month or so, Mr. Wilhite had created the first GIF, a picture of an airplane. Today the file format is typically used for looped videos or animations, which populate social media and office Slack channels and serve as a pop culture shorthand — a fast, wordless way to express emotions like joy (Brad Pitt dancing in “Burn After Reading”), embarrassment (Homer Simpson retreating backward into a hedge), excitement (Michael Jackson eating popcorn) or approval (a bearded Robert Redford in “Jeremiah Johnson,” nodding with a smile as the camera zooms in).

The GIF “caught on pretty fast with developers,” Trevor recalled in a phone interview, adding that Mr. Wilhite “was the architect of GIF, no question about it.” He said that while the file format was not originally created for animation, Mr. Wilhite had designed the GIF so that it could be stretched and extended, helping to turn it into an animated medium. The format endured even after the creation of rivals such as PNG, and became ubiquitous with the advent of Netscape and other Internet browsers, with “Under Construction” GIFs populating new websites and animated GIFs popping up on Myspace pages in the early 2000s.

By 2012, when Oxford Dictionaries named GIF the U.S. word of the year, the term was being used as a verb, not just as a noun. The word had also sparked a fierce debate over its pronunciation, which the magazine Mother Jones once described as “the most absurd religious war in geek history”: Was it a soft g like Jif, the peanut butter brand? Or a hard g, as in “gift?”

Mr. Wilhite weighed in on the issue in 2013, shortly before he was awarded a Lifetime Achievement Webby Award for his invention. “The Oxford English Dictionary accepts both pronunciations,” he told the New York Times. “They are wrong. It is a soft ‘G,’ pronounced ‘jif.’ End of story.”

Stephen Earl Wilhite was born in West Chester Township, Ohio, on March 3, 1948. At age 17, he was shot in the face during a reenactment of a Civil War raid at a town sesquicentennial celebration, where one actor apparently used a real bullet instead of a blank cartridge. Mr. Wilhite was hospitalized for about six weeks but went on to graduate high school as one of the state’s “10 top science students,” according to an Associated Press report about his recovery.

He studied computer science and engineering at Ohio State University before joining CompuServe, shortly after the company was founded in Columbus, Ohio, in 1969. In addition to creating the GIF, he developed compilers and designed the architecture for the company’s client-server environment, which Trevor described as a kind of precursor to Web browsers. “Personally I think that was his greatest accomplishment,” he said. “CompuServe ended up with maybe 2 million subscribers, and we wouldn’t have anything like that without” Mr. Wilhite’s software work.

In addition to his wife of 12 years, the former Kathaleen Bauer, survivors include a son, David, from an earlier marriage that ended in divorce; four stepchildren, Rick Groves, Robin Landrum, Renée Bennett and Rebecca Boaz; four sisters; 11 grandchildren; and three great-grandchildren.

Mr. Wilhite remained at CompuServe after its online services branch was sold to AOL, and retired after suffering a stroke in 2000. He kept busy by going on weeks-long RV trips and expanding his model train collection, which occupied an entire room at the country home he built in Milford, Ohio. For years, he also rode dirt bikes, sometimes frightening friends who saw him racing up dirt hills and pathways.

As Trevor told it, Mr. Wilhite had once enjoyed riding up a steep hill near Mansfield, Ohio, where he would fly over the top and race down the other side. On one such ride, he decided to stop at the summit rather than continue on, only to realize as he braked that the far side of the hill had been “dug out,” as Trevor put it.

“If he had just kept going, he would have gone right over the edge and there would have been no GIF.”