OSError: cannot identify image file 'xxxxx.jpg'

[guardrex]

I'm getting an intermittent issue while processing JPEG files.

System: Raspberry Pi
OS: Arch Linux
Python: 3.4.1
Pillow: 2.5.3

Exception:

File "/usr/lib/python3.4/site-package/PIL/Image.py", line 2256, in open
% (filename if filename else fp))
OSError: cannot identify image file 'xxxxx.jpg'

My image files are saved out of PiCamera; however, the same issue also crops up with images that Pillow saves. I'm processing images in a loop. There is a two-second delay between processing each image. It's not related to memory: I monitored available memory, and that was stable before and after the exception.

After processing a few images, the exception is thrown, then my Pillow code simply re-processes (re-opens) the same image and Pillow opens it and processes it normally ... same file ... no changes ... just two seconds later after the exception is thrown. Therefore, it seems something is amiss in the library.

[guardrex]

Is it possible that somehow PiCamera isn't finished writing the file? Pillow is running in a separate thread from PiCamera in my app, and I wonder if this is a simple matter of Pillow trying to open the file and read it before PiCamera is finished writing the file?

[guardrex]

Upon further testing, this seems to be the case. The file isn't completely written when Pillow tries to open it.

[hugovk]

@guardrex Fixed by rubber duck debugging :)

[guardrex]

Indeed, we have entered "The Cone of Answers" on this one. Just as well: I searched, and there wasn't much on this exception under these conditions.

Part of the problem is that the exception is too generic to be of much help. I recommend (if possible) that the exception for a corrupt file be distinguished in some way from an IO error. Better yet, if there were any way to signal that the file is open or locked by another app, then throw a 3rd type of exception. A more detailed exception would have led to a quick resolution of my issue.

[jcavejr]

Sorry that I'm commenting on this so late. I'm wondering if you could share your solution to this issue? I'm on a raspberry pi getting the same error. I've tried every solution I've read so far, but I'm leaning towards my issue being the same as yours. Only problem is I'm not sure how to go about fixing it. Thanks in advance for any replies!