Following Frances' lead suggests the image is corrupt and needs to be replaced. (Jargon alert – the 'image' is a copy of the phone's operating system, not a photograph.)
Ordinary users rarely need to worry about the operating system unless it goes wrong as it has here, cause unknown.
Attempting to start, the phone has detected the image is corrupt and is attempting to download and install a new one from a PC. What's required on the PC is:
- A bunch of files provided containing a clean operating system. These are provided by Samsung and have to match the phone. A quick search found developer images but not user images, but my Google-fu is weak. Once found these are copied to the PC.
- A program called Odin, available here. This detects an Android phone connected to the PC with a USB cable and allows a new image to be burnt on the phone. The screenshot shows the phone has found an image error, has entered recovery mode, and is waiting for Odin.
I've fixed equivalent Windows and Linux OS corruptions, but not Android (or Apple). The process can be fiddly and using hard to drive tools. I've no idea if Odin is wonderfully easy to use or a complicated pig stuffed with unexplained options and weird abbreviations! Odin available for download is said to be proprietary Samsung software that's been pinched – slightly worrying!
Unless I fancied an adventure, I'd give it to an expert to fix. Harry might try Samsung's service website to find one, or these people who come to the door and claim to be cheaper.
Dave