Facebook Inc's photo-sharing social network Instagram says the service is fully functional after a problem that caused an outage for some users was resolved.
However, Instagram did not specify the number of people or the regions affected.
Users took to Twitter to complain about the outage, tweeting jokes and comments along with the #instagramdown hashtag.
"Hi five! If you come to twitter and checking if the Instragram is down," @kneelonyeahtea tweeted.
DownDetector.com, a website that monitors outages, showed there were more than 32,000 incidents of people reporting issues with Instagram at its peak but that figure quickly dropped to about 500 reports.
Instagram had started having issues at 7.21pm on Monday (11.21am AEDT on Tuesday), according to the website.
