Solution
When importing images to Digital Photo Professional Express, and the [ ] or [ ] icon appears, it means that the images are not supported by Digital Photo Professional Express, thereby the images cannot be imported.
Digital Photo Professional Express does not support CR2 images, thereby when using Camera Connect to import images, the ''failed to save image'' message will appear, as well as the [ ] icon next to the image.
Choose [ ] from Digital Photo Professional Express -⋗ When choosing [Import from camera roll (JPEG)], to import images, the [ ] icon appears on the top left corner of the image (*). This means that Digital Photo Professional Express does not support it and cannot import the images.
* JPEG images with over 33 million pixels or other format