RE: "Right-click on the image in Windows and select Properties and then "Details" tab and look for "Bit depth" line. If it says 32bit, it is a CMYK jpeg. 24bit is normal RGB and 8bit is grayscale."
Bit Depth for a problem image is 24. But, it also lists creation software as "Adobe Photoshop CS6 (Macintosh)" and Color Representation as "Uncalibrated", so maybe that is the problem?