How the image data is formatted depends upon the class of the image as specified (or not specified) by the value of the class key in the header.ĭirectClass images are continuous-tone, images stored as RGB (red, green, blue), RGBA (red, green, blue, alpha), CMYK (cyan, yellow, magenta, black), or CMYKA (cyan, yellow, magenta, black, alpha) intensity values as defined by the colorspace key. Since I'm not versed in this subject, this ImageMagick page might help understand what's going on: The main difference appears to be in the class definition of both images. Thanks to the awesome ImageMagick tools, I found some clues on what is probably going on here. These are similar images to the ones provided.
Just to make our lives easier, I'll name the images: I have no idea of the impact of such formats when processed by pdfTeX.
Disclaimer: I'll try to write a technical explanation of what I found, but I'm not versed in those image witchcrafts.
