Bigger pictures also will give advertisers a larger canvass to make their marketing pitches. Facebook is hoping marketers will seize the opportunity to develop more creative ways to entice and intrigue customers so advertising can become a more acceptable fixture on the social network.More than anything else, the changes are meant to make Facebook a more fun place to hang out. "This is all about keeping people engaged," Blau said. Although Facebook's website remains one of the Internet's top destinations, there have been early signs that the social network is losing some of its pizazz, particularly among younger Web surfers who are starting to spend more time on other fraternizing hubs such as Tumblr, Pinterest and Instagram, a photo-sharing site that Facebook bought for $521 million last summer. A phenomenon, known as "Facebook Fatigue," was recently documented in a report from Pew Research Center's Internet and American Life Project. The study found that about 61 percent of Facebook users had taken a hiatus for reasons that range from boredom to too much irrelevant information to Lent. That's a worrisome trend for Facebook because the company needs to ensure that its audience keeps coming back so it can learn more about their interests and, ultimately, sell more of the advertising that brings in most of the company's revenue. "I don't think it had turned into a crisis, but Facebook was probably seeing some internal data that was telling them they needed to do something," said Greg Sterling, a senior analyst for Opus Research. Facebook has been struggling to find the right balance between keeping its fun-loving audience happy and selling enough ads to please investors who want the company to accelerate its revenue growth. Wall Street seems to think the redesigned News Feed might be a step in the right direction. Facebook's stock gained $1.13, or 4.1 percent, to close Thursday at $28.58. The shares still remain 25 percent below the $38 that they fetched in Facebook's initial public offering last May.