Why am I getting the error: "Not a JPEG file: starts with 0x89 0x50"

Your 'JPEG' file has wrong filename extension 'jpg' or 'jpeg', it's real type is most probably a PNG file.

Just try to rename file name from 'xxx.jpg' or 'xxx.jpeg' to 'xxx.png'.

Under most circumstances, programs distinguish file type with filename extension for convenience, however, if we specify a wrong filename extension(like 'jpg') to a file in other format(like a PNG file), the program will still try to load the PNG file with JPG library, an error will certainly be thrown to user.

Actually, different type of files always have different file header (first 1024 byte)

Here's a quick pass to check real type of the file on Unix-like platform:

using the "file" command, like:

file e3f8794a5c226d4.jpg 

and output is

e3f8794a5c226d4.jpg: PNG image data, 3768 x 2640, 8-bit/color RGBA, non-interlaced

which will print file information details, and we can also check if the specified file has been destructed.

Your file is not a JPEG file, it's just been renamed from a PNG to a JPEG somewhere along the way. Some programs will open this as a recognised file extension and infer the type from the prefix, but obviously not the one you're using.

The file is actually a PNG with the wrong file extension. "0x89 0x50" is how a PNG file starts.