When I recently saw this issue, I created a ticket and provided a couple of affected chunk files. Now I did some further investigations and identified what these files have in common: Itâ€™s the first two characters. All my affected files start with â€œP1â€, â€œP2â€, â€œP3â€, â€œP4â€, â€œP5â€, â€œP6â€ or â€œP7â€. The rest of the file does not matter and the issue is not restricted to chunk files. It applies to any file, even to ordinary text files, which start with such a header (when I upload a .txt file to ACD with something like â€œP1 bla bla â€¦â€, it shows up under â€œPhotos & Videosâ€ with â€œCould not Displayâ€).
I finally found the reason, why ACD identifies these seven two-byte strings as picture headers: These strings (P1, P2, â€¦ P7) are the seven magic numbers of the Netbpm format (portable anymap format).
Maybe this help to develop a solution.