"Moment by moment, your Twitter profile shows the world who you are," the company said in a blog post. "Starting today, it will be even easier (and, we think, more fun) to express yourself through a new and improved web profile."
As part of changes coming in the next few weeks, users who access Twitter via the web will notice larger photos on their profile pages. Besides profile photos on the left corner of the page, the redesign includes a large banner photo that resembles the big rectangular cover photos on Facebook pages.
Users will be able to "pin" one of their tweets to the top of the page to give others an idea of the topics they like to tweet about. In addition, tweets that receive the most interest from other users will appear slightly larger.
The more visual look is an attempt to attract people who may be intimidated by Twitter's onslaught of text filled with quirky acronyms, at-symbols and hashtags. The changes come at a time when Facebook is adding features to its site that are Twitter-like, highlighting the way the two companies are jockeying for people's time and advertisers' cash.
Is Twitter saying a picture is worth 140 characters? Perhaps not. The new profiles do not apply to Twitter's mobile app, which is a more popular way to access the service than the website. Mobile is also where Twitter earns most of its money. EMarketer expects about 77% of Twitter's estimated 1.1 billion dollars (£658m) in advertising revenue to come from mobile this year.
Even so, Twitter has acknowledged that it needs to reach a bigger audience. CEO Dick Costolo described the effort in broad terms during the company's February earnings call with analysts.
"By bringing the content of Twitter forward and pushing the scaffolding of the language of Twitter to the background, we can increase high quality interactions and make it more likely that new or casual users will find the service as indispensable as our existing core users do," he said.
Mr Costolo also promised more visually engaging content, of which the profile page redesign is just one example. Last autumn the company decided to make users' feeds more visual by including previews from Twitter photos and Vine videos.
Twitter's first-quarter tally of users signalled that growth is slowing on the service. The company added just nine million new monthly users in the fourth quarter, only one million of which came from the US. It added an average of 16 million new accounts in each of the first three quarters of 2013.
Twitter said in February that it had 241 million users at the end of 2013. By comparison, Facebook boasts some 1.23 billion users, while WhatsApp, the messaging service Facebook is buying for 19 billion dollars (£11.3bn), said it had 400 million active monthly users last December.
Twitter has not yet reported its first-quarter financial results, so it is hard to tell if the slowdown is a sign of trouble or just a blip.
EMarketer analyst Debra Aho Williamson said in a recent report that Twitter's user base "may be growing more slowly than expected, but the social service has steadily increased its ad revenue and shown that its ads can drive engagement and interaction".
Noah Elkin, executive editor at eMarketer, said advertisers "love the engagement they get on Twitter". That said, he added that the company was still under pressure to grow.
The redesigned profile page, Mr Elkin said, will probably have a "relatively minimal impact" on Twitter's advertising revenue, "unless and until" the company brings the new look to its mobile app.