I have encountered problematic .JPG file and I've decided to use Hex View function of DOpus Picture Viewer to look what is inside that file. When that file is opened a message "Unable to load 'IMG_0004.JPG" as a picture" is displayed. When I click on "Hex View" button, viewer's window disappears.
I was able to hexview that file using other method. First I've opened a correct JPEG file, then switched to Hex View, and then I've opened IMG_0004.JPG via menu function File/Open... . It appears that the whole file is filled by zeros.
In case that information would be needed to reproduce the behaviour: file size is 2 643 971 bytes.
Directory Opus Pro 11.16.1 (Beta) Build 5770 x64
OS 6.2 (B:9200 P:2 T:1) SP 0.0