The seemingly normal wallpaper of a lake has bricked the phones of dozens of android users. It might sound like a hoax at first; that’s what i thought too. But going into the details revealed shocking yet interesting information on how image format on phone works.
Almost a week ago, a Twitter account @UniverseIce warned Samsung users, especially, to not use a picture as their wallpaper.
Never set this picture as wallpaper, especially for Samsung mobile phone users!
It will cause your phone to crash!
Don’t try it!
If someone sends you this picture, please ignore it. pic.twitter.com/rVbozJdhkL
— Ice universe (@UniverseIce) May 31, 2020
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But it’s the Internet and we live in a society. People took it as a joke or tried being adventurous.
What happened next was already predicted by @UniverseIce; their phones started crashing. The thread was filled with users saying they bricked their phones.
Don’t try this it actually crashed my samsung phone
— Aneesh Gupta (@aneeshguptaag) May 31, 2020
But that is not where the tragedy ended. It wasn’t just a Samsung issue, it’s an Android issue.
— Sebastian (@seb3153) May 31, 2020
But, what causes the phones to crash so terribly?
The explanation is rather technical and tricky.
To clear out any confusions beforehand, the image hasn’t been tampered with at all. It seems highly unlikely that someone took this picture with any malicious intent. It is just a beautiful picture of a lake, nothing more. But, it will crash your android device and make you lose all your data.
Starting with the basics, there’s three types of colors that make up all the other colors on the mobile phone screens: Red, Green, and Blue. Of all the colors that a person can see with their eyes, a mobile phone can only show a small subset of it.
Talking about the OS at hand, Android only understands sRGB color space. For the sake of consistency, almost all screens are calibrated to the sRGB standard by default.
But, that doesn’t mean there’s no other color spaces. AdobeRGB, Rec 709, and ProPhoto are some other color spaces. The difference between these color spaces is the set of colors they contain.
To better clarify the difference between these color spaces, here’s the same picture in three different color schemes.
It is quite visible why it can be tempting to use a bigger color space as it adds to the saturation of the image. Apparently, that is what the photographer of the lake wallpaper did. Looking into the properties of the image, the picture is in ProPhoto RGB.
How can an innocent attempt to improve a picture result in dozens of phones crashing?
The answer is in hidden in one tiny pixel. There’s just one pixel in this image that was able to wreak havoc on the Android OS.
The Google color engine uses sRGB color space and it assigns each color a certain luminance. Luminance is sort of a weighted average brightness assigned to each color, based on how it is perceived by humans. Green has the highest luminance, then comes red, and then blue. The assigned weightages are 0.2126, 0.7152, and 0.0722 for red, green, and blue respectively. Each color component is multiplied by its luminance and then added. Since, the maximum value of a component is 255, the sum for a pixel shouldn’t exceed 255.
But, that is where this picture defies the laws. Google rounds off each product before taking the sum. As a result, the sum of one specific pixel exceeds 255 and comes out to be 256. Usually, when the OS runs into something it cannot process, it tries to fix it or close the process.
But, what if you set such a picture as the wallpaper?
As explained earlier, the OS tries to close the process every time it runs. Unfortunately, the wallpaper process runs every time the screen is turned on. Thus, the phone throws itself into this spiral of forced closes and the phone is bricked.
But, no need to worry. According to the same account that tweeted about this bug, Samsung has already fixed the issue and will rollout the fix in the next firmware update.
Update: Samsung has received feedback on this type of bug in mid-May, and has resolved this issue. Just wait for the subsequent firmware update and do not take the risk. pic.twitter.com/oa7rxnkSkb
— Ice universe (@UniverseIce) June 1, 2020
Other companies will soon release the fix with consequent updates too as this is not a difficult bug to fix.
Disclaimer * For now, steer clear of this wallpaper bug, we’ve warned you and are not responsible for any loss if you choose to try this.