For the past week Iran has been gripped by protests. Thousands of Iranians have taken to the streets to demonstrate against government corruption, unemployment and the weak economy.
Despite heavy restrictions on social media, some videos and pictures have found their way online, including those appearing to show protesters vandalising buildings and being fired at by government forces.
The authorities blocked access to Instagram and the messaging app Telegram in an attempt to stop calls for protests and the sharing of videos and photographs online, but then many images had already been circulated.
One of the most widely shared images is of a woman taking off her white head covering and waving it on a stick in an apparent act of defiance against Islamic rule. Although the image is genuine, it was not taken during the current unrest.
The demonstrations began on 28 December in Mashhad, the country's second largest city. In the days that followed a wave of spontaneous demonstrations broke out in many other towns and cities, with protesters calling for an end to the rule of Iran's Supreme leader, Ayatollah Ali Khamenei.
The image of the woman waving the headscarf was first posted on social media one day before the protests began by Masih Alinejad, a US-based Iranian journalist.
Ms Alinejad is also a women's rights activist and the founder of two social media campaigns, My Stealthy Freedom and White Wednesdays.
My Stealthy Freedom encourages Iranian women to post photos and videos of themselves without the mandatory headscarf in public. White Wednesdays, which began in 2017, urges women to wear white clothing every Wednesday to protest against Iran's strict dress code.
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Ms Alinejad posted an image of the woman on her Instagram page, attributing her action to the White Wednesday campaign.
همین امروز چهارشنبه خیابان انقلاب - روبروی نان فرانسه، دختری که روسری خود را به چوبی اویزان کرده بود و در هوا تکان می داد. این دختر پس از پایان کار توسط نیروهای نظامی دستگیر و جوانانی هم که از این دختر حمایت کردند بازداشت شدند . دختر از آزادي و حق انتخاب پوشش حرف مي زد و جوانان ديگري هم او را حمايت مي كردند. جنبش مطالباتی در حال پیش روی است به نظر شما آيا نظام به مطالبات به حق اجتماعی پاسخ خواهد داد ؟ پليس ايران امروز يك قدم عقب نشيني كرد و گفت از اين پس كسي به جرم بدحجابي بازداشت نمي شود. #چهارشنبه_های_سفید #چهارشنبه_های_بدون_اجبار #whitewednesdays
On the same day she was filmed in Tehran's busy Enghelab Street, the authorities in the capital announced that women caught in public without their hair covered would no longer be arrested.
Those who do not cover their heads correctly will now have to attend Islamic educational classes.
Images and videos of the woman standing on a box waving her headscarf began to be widely shared by those who do not believe the reforms go far enough, and by anti-government protesters disillusioned with the clerics in power.
As a consequence, the young woman has become the face of Iran's protest movement which has seen the mobilisation of hundreds of Iranian women. Many have also described her as "Iran's Rosa Parks".
A popular Twitter account posted in Persian: "A girl standing against mandatory hijab has become the symbol of resistance and civil disobedience of Iranian women. Rosa Parks did not bow down to oppression."
Tributes continue to be paid to the woman's act of defiance. This Twitter user posted that the flowers left on the box was where she allegedly made her protest.
Hundreds of social media users have also changed their avatars and profile pictures to a colourful graphic of the headscarf-waving woman.
"براي دختر روي سكوي خيابان انقلاب. كاري كه او كرد اعلام نارضايتي اش بود به شيوه اي مدني و مسالمت آميز. درست شبيه به كاري كه اين روزها مردم سراسر ايران دارند انجام مي دهند. بيانِ نارضايتي و اعتراض شان به وضعيت موجود. امتداد صداي هم باشيم حتي اگر بگويند هيسسسس الان وقتش نيست. زنان اين روزها شانه به شانه ي مردان ايستاده اند و شجاعانه عليه ظلم فرياد مي زنند. هيچ وقت فريب كساني را نخوريم كه ميان زنان و مردان جدايي مي اندازند و هيس هيس مي كنند. نبايد اين زن را تنها بگذاريم و نسبت به وضعيتش بي تفاوت باشيم. هميشه وقتش است كه از هم حمايت كنيم و در همه ي شرايط حتي وسط تجمع ها و تظاهرات هم حجاب اجباري را كه نمادِ سركوب و تحقير انسان است دور بياندازيم." #چهارشنبه_های_سفید #چهارشنبه_های_بدون_اجبار #whitewednesdays #نه_به_حجاب_اجباری
Although the young woman's identity and fate remains unknown, she has become a symbol of liberty and hope for many supporting in the anti-government protests.
She is also not the first Iranian woman to become the face of political unrest.
Footage of the death of Neda Agha Soltan drew worldwide attention during the mass protests in 2009 that were triggered by a disputed presidential election.