Apple’s HEIC photo format isn’t widely supported and that causes problems when students upload photos during online exams.
But the testing portal doesn’t support the default format on iOS devices and some newer Android phones, HEIC files. HEIC files are smaller than JPEGs and other formats, thus allowing you to store a lot more photos on an iPhone. Basically, only Apple (and, more recently, Samsung) use the HEIC format — most other websites and platforms don’t support it. Even popular Silicon Valley-based services, such as Slack, don’t treat HEICs the same way as standard JPEGs.
I wish more websites would support HEIC/HEIF. It should be a no-brainer since the file size is smaller than JPG and supports a wider color gamut.