Killer GIFs: How Can an Animated GIF Become a Weapon?

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Killer GIFs: How Can an Animated GIF Become a Weapon?

Before we tackle that question, let’s step back in time 20 years. Late on a December afternoon in 1997, thousands of Japanese children simultaneously collapsed into seizures across the nation – 685 were hospitalized, some for more than two weeks.

It was later determined that they had all fallen watching exactly the same scene in a new episode of Pokemon. In episode #38, ‘Electric Soldier Porygo’, Pikachu uses his lightning attack to destroy incoming missiles. It turns out that the animators had used a fast red and blue strobe effect to create the lightning which had unwittingly induced photosensitive epileptic seizures in a substantial number of viewers.

Pikachu - pokemon

Of course, this was a complete accident and a huge shock for Pokemon’s creators. In fact, the anime studio took a 4-month hiatus to investigate the incident and steps were taken to avoid all high contrast strobing animations in future.

But not all animators set out with such benign intentions.

Animating with Intent to Injure

Last friday, a Maryland man, John Rayne Rivello, was indicted to stand trial for attempted murder with an animated GIF.

John Rayne Rivello

In December last year, Rivello had taken extreme exception to writings of a Newsweek journalist Kurt Eichenwald and decided to take action. Aware of Eichenwald’s photosensitive epilepsy, Rivello created a large, flickering animated GIF with the words ‘You deserve a seizure for your post’ across the bottom. A short time later, Eichenwald’s wife found the writer collapsed and called 911.

The FBI charged Rivello with ‘criminal cyberstalking with the intent to kill or cause bodily harm’. Eichenwald’s lawyer argues that in this situation, tweeting this carefully crafted GIF directly to his client was no different to mailing an explosive device or a poison.

Rivello faces up to 10 years jail.

So, could designers accidently trigger seizures?

The good news is, probably not – it’s relatively difficult to accidentally trigger a seizure in vulnerable users. According to, problematic content would need to continuously flicker between 5 and 30 times per second. While we might create a flickering UI element, it’s less likely that it will continually animate.

The flicker source also needs to be large – few animated spinners and loading graphics are going to be big enough to cause problems. In practice, movies, TV, entertainment lighting, video games and even pinball machines typically present more problems than the web does.

Arguably, the single biggest risk for unwary designers are static graphics with special qualities. High contrast optical illusions – like the small section of image I’ve included above – can present serious issues when used in large panels and backgrounds. Although the image isn’t animated, it appears to move.

Though it’s unlikely, this is a scenario that could occur quite unintentionally and should certainly be considered when creating patterned backgrounds.

Frequently Asked Questions about Animated GIFs as Weapons

How can an animated GIF become a weapon?

An animated GIF can become a weapon when it is used maliciously to trigger health conditions such as epilepsy. Certain patterns or flashing lights in GIFs can induce seizures in people with photosensitive epilepsy. This is a form of cyberattack that can cause serious harm to the targeted individual.

What is photosensitive epilepsy?

Photosensitive epilepsy is a type of epilepsy where seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights, bold, regular patterns, or regular moving patterns.

How can I protect myself from harmful GIFs?

You can protect yourself by adjusting your device settings to reduce the risk. For instance, you can decrease the brightness of your screen, increase the distance between you and the screen, use the device in a well-lit room, and avoid looking at screens for a long time without breaks.

Are there any laws against using GIFs as weapons?

Yes, using a GIF to cause harm to someone can be considered a form of assault and can be punishable by law. In some jurisdictions, it can be classified as a cybercrime.

How can I report a harmful GIF?

If you come across a harmful GIF on a social media platform, you can report it directly to the platform. If you believe you are the victim of a cyberattack, you should report it to your local law enforcement agency.

Can all GIFs trigger seizures?

No, not all GIFs can trigger seizures. Only those with certain patterns or flashing lights can potentially trigger seizures in people with photosensitive epilepsy.

How common is photosensitive epilepsy?

Photosensitive epilepsy is not very common. It affects approximately 3-5% of people with epilepsy. However, the impact can be severe for those affected.

Can I develop photosensitive epilepsy from watching GIFs?

No, you cannot develop photosensitive epilepsy from watching GIFs. This condition is usually genetic and often starts in childhood or adolescence.

Are there any tools to check if a GIF is safe?

There are no specific tools to check if a GIF is safe. However, if you have photosensitive epilepsy, you can use screen filters or special glasses that can help reduce the risk of a seizure.

What should I do if I experience a seizure after viewing a GIF?

If you experience a seizure after viewing a GIF, seek immediate medical attention. Afterward, report the incident to the platform where you found the GIF and to your local law enforcement agency.

Alex WalkerAlex Walker
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Alex has been doing cruel and unusual things to CSS since 2001. He is the lead front-end design and dev for SitePoint and one-time SitePoint's Design and UX editor with over 150+ newsletter written. Co-author of The Principles of Beautiful Web Design. Now Alex is involved in the planning, development, production, and marketing of a huge range of printed and online products and references. He has designed over 60+ of SitePoint's book covers.

AlexWepilepsyflickergif animationpokemonstrobe effect
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