Written by Emily Leng, Writeup by Jester
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Did you know you can do arithmetic with images too?
This problem is quite simple. The hint gives us an extremely useful website that allows us to perform "arithmetic" on the images provided.
After converting the pngs to the needed format on the website, you can simply try it out until you get a QR code. (Upload the images on a website) After trying all of them, we find that the correct QR code is actually XOR. Afterwards, you can scan the QR code, which links you to the flag.
pixelsmatterinQRs