Police in Egypt said on Tuesday they had arrested "a screen technician" after anti-government images were broadcast in a working class neighbourhood of Cairo.
The technician confessed to putting "offensive expressions on an advertising screen", the interior ministry said in a statement.
On Sunday evening, a street-facing screen above a storefront in western Cairo's busy Faisal neighbourhood displayed a slideshow of altered images protesting against President Abdel Fattah al-Sisi's rule.
Footage of the screen quickly spread online as a rare show of protest in Egypt, where a years-long crackdown has curtailed nearly all dissent.
The interior ministry statement said the technician commandeered the screen "at the instigation of online groups run by Muslim Brotherhood members abroad".
The group was outlawed after Sisi -- then army chief -- ousted Islamist president Mohamed Morsi from power following popular protests in 2013.
Sisi was elected president the following year.
On Monday, large advertising screens on highways in Cairo showed old footage of Islamist attacks on the security services, carried out following Morsi's ouster.
The billboards carried the messages "So we don't forget" and "The Brotherhood is a terrorist group".
In the decade since Sisi took power, Egypt, ranked 136th out of 142 countries in the World Justice Project's rule of law index, has been accused of vast human rights violations.
Rights groups say the authorities in Egypt have detained tens of thousands of people as political prisoners -- Islamist as well as secular and liberal activists -- many of them are still imprisoned in harsh conditions.