Yahoo chief executive Marissa Mayer, maintaining that her ambition was to make Flickr "awesome again," said the new site will showcase "bigger images" and create a user experience that is "more immersive, more expressive."
Mayer's announcement of the Flickr makeover came only hours after the company announced it was buying Tumblr for $1.1 billion. Referring to Tumblr, Yahoo promised "not to screw it up."
Mayer, a Google veteran who joined Yahoo as chief executive last summer, Monday referred to Flickr as a once-shining acquisition "that didn't fare so well" and vowed that Tumblr would not follow a similar path.
Mayer described Monday's dual announcements as consistent with her ambition to make Yahoo an "Internet services company" that focuses on "improving user experience."
Some analysts have criticized the $1.1 billion Tumblr deal as overpriced given that the company has a scant $13 million in revenues and no profits.
But Mayer said that Tumblr's users of some 300 million per month complements Yahoo's 700 million per month, making a total of some 1 billion users per month, a huge set of eyes that will appeal to advertisers.
The remade Flickr aspires to transform a consumer experience that had become flat with excessive text and dull, uninspired photos.
Under the new Flickr, photos upload in full resolution and adapt "wherever" users desire, such as smartphones, tablets or social networks such as Facebook and Twitter, said Yahoo senior vice president Adam Cahan.
The showcase element is a free terabyte of space to store photos; enough capacity to store up to 537,731 images, Cahan said. That is more space that any user could possibly fill in a lifetime, Yahoo officials said.
"We wanted it to be unlimited," Cahan said.
The revamped website, which went live Monday evening, also has a new look, cutting out words and user messages and instead featuring larger photos without text set against a sleek black background.
Mayer said Flickr's current subscription pool is in the "tens of millions." She declined to release the company's targets for growing subscriptions.
Mayer said Yahoo benefits from a "really healthy" revenue stream, largely from advertising.
The new Flickr will employ new advertising formats that Yahoo is still developing. Users who want to opt out of advertising can pay $49.95 a year to access an ad-free version of Flickr.
Mayer said she has four more product launches scheduled for the coming weeks.
She boasted that the recent stream of activity has increased the "velocity" within Yahoo, which has been viewed by some as a fallen technology star following the rise of Google and some other companies.
Mayer, who was joined by New York Mayor Michael Bloomberg, also announced that Yahoo had settled on a New York City headquarters. It will be in the former New York Times building in Times Square.
"Twenty years ago if you looked out here you'd see plenty of yahoos, but now the Yahoos will make an honest living and help us grow," Bloomberg said in a joking reference to the area's seedy past.
Bloomberg said that the moves show the city has become "a big player" in the technology world.