That is a CMYK jpeg. You can convert it to RGB using, for example, the convert program from ImageMagick, like this
convert cmyk.jpg -colorspace sRGB rgb.jpg
In any case the next release of calibre will contain code to automatically detect CMYK jpegs and convert them to RGB when producing EPUB files.
That is a CMYK jpeg. You can convert it to RGB using, for example, the convert program from ImageMagick, like this
convert cmyk.jpg -colorspace sRGB rgb.jpg
In any case the next release of calibre will contain code to automatically detect CMYK jpegs and convert them to RGB when producing EPUB files.