UPDATE 3:10 pm ET on October 16

It's déjà vu all over again. Twitpic announced on Thursday that it is once again shutting down, just a few weeks after the startup announced it would not be forced to close thanks to an acquisition by an unidentified party.

"I’m sincerely sorry (and embarrassed) for the circumstances leading up to this, from our initial shutdown announcement to an acquisition false alarm," Twitpic founder Noah Everett wrote in a short update. Twitpic now plans to shut down on October 25.

It's with a heavy heart that we re-announce that Twitpic will be shutting down again. More details on our blog http://t.co/LCH7ZTQJHe — TwitPic (@TwitPic) October 16, 2014

In early 2009, Janis Krums tweeted a remarkable picture of a US Airways plane partly submerged in the Hudson River off of New York City. That image quickly went viral and helped put Krums and Twitter on the map.

At the time that image was posted, though, Twitter did not have a native photo-sharing feature so Krums used Twitpic, one of a couple photo tools that worked with Twitter. On Thursday, Twitpic announced that it will be shutting down later this month. The reason: Twitter.

"A few weeks ago Twitter contacted our legal demanding that we abandon our trademark application or risk losing access to their API," Noah Everett, Twitpic's founder, wrote in a blog post announcing the shut down. "This came as a shock to us since Twitpic has been around since early 2008, and our trademark application has been in the USPTO since 2009."

Everett added: "Unfortunately we do not have the resources to fend off a large company like Twitter to maintain our mark which we believe whole heartedly is rightfully ours. Therefore, we have decided to shut down Twitpic."

When reached for comment by email, Everett told Mashable that the legal dispute marked the first "instance of pressure from Twitter" since Twitpic launched in 2008.

"As far as we know, we have been on good terms," Everett said of his relationship with Twitter prior to a few weeks ago. "We worked with our legal and Twitter’s to see if they would drop this case against our mark, it had been going back and forth for a few weeks."

Thank you everyone who used @Twitpic & allowing me the honor of helping share your experiences. I will miss & cherish our days of Twitpic! — Noah Everett (@noaheverett) September 4, 2014

Despite its role in helping Twitter spread viral photographs like the plane on the Hudson early on, Twitpic has had strained relations with the social network since at least 2011. That year, Twitter introduced its own photo-sharing, effectively competing with third-party tools like Twitpic. The next day, Everett responded by introducing a mocking clone of Twitter called Heello.

More recently, Twitter cracked down on a number of third-party applications in order to ensure "a consistent Twitter experience."

A rep for Twitter told Mashable that it is "sad" to hear Twitpic is shutting down, but that legal action was necessary to "protect our brand."

"We're sad to see Twitpic is shutting down," the rep said in a statement. "We encourage developers to build on top of the Twitter service, as Twitpic has done for years, and we made it clear that they could operate using the Twitpic name. Of course, we also have to protect our brand, and that includes trademarks tied to the brand."

Everett had a slightly different take on the situation after being shown Twitter's statement.

"Basically Twitter gave us an ultimatum, give up your mark or risk losing your API access which is Twitpic’s life blood," he said by email. "We could not in good conscious just give up our rightful ownership to the Twitpic mark when forced to do so even though we don’t have the funds to fight it."

Once Twitpic shuts down on September 25, Everett says he will focus his efforts on Pingly, a messaging app that he's been working on lately.