Re: [Gimp-user] Corrupted JPEG

[Elle Stone <ellestone ninedegreesbelow com>]

On 01/04/2014 04:27 PM, Phil wrote:
> Hi All
>
> Apologies to all for not starting a new thread, i have been an avid
> reader of the emails for a while now, and read most of what people put
> here, so sorry Michael & Jay who pointed that out to me..
>
> ill try and answer all questions about whats what etc.
>
> I believe the original pictures, that were taken in 2011, were taken
> directly of the camera via USB cable, these were then stored on my
> friends computer, and these were corrupted. I didnt notice it much at
> first, as she asked me to look at something different (spamware), but
> her screen saver, which must have read the pic folder, showed pictures,
> that looked to be corrupted, i initially thought that these were to big
> for the screen saver to handle, and dismissed them.
>
> She still had the memory card, and the thumbnails, still showed fine on
> camera preview screen, so she thought they were safe. But luckly, she is
> not an avid photographer, and didnt even wipe the card! After that, i
> Borrowed the card, and used photorescue (it saved me once so i was more
> than happy to pay for it after my canon 350d corrupted a card that was
> not quick enough), and it again found the same pictures corrupted.
>
> So then began my quest for finding information/utilities to undo/correct
> the files.
>
> The Card reader is my own, that i ran the software recovery on, so with
> the fact that since she has bought a new memory card, and it worked
> fine,  i assume its a faulty card? so i took a copy of what she had.
>
> DSC0001.jpg seems to be fine, this is the first card picture on the
> card, i dont know if any were taken before, ie new card or new camera,
> but i could find out if needed. DSC0002.jpg, that is ooo 75% ok, but
> after that, all the remaining 221 pictures are damaged, all only showing
> about 5%.
>
> I ran imagemagick "mogrify -strip name-of-file.jpg", that ella
> suggested, and it gave me a comment unsupported marker type 0x3a
> 'dsc0002.jpg' @warning/jpeg.c/jpegerrorhandler/313.
>
> I did try loading into Gimp 2.8.2 on debian 7.2 after the imagemagick
> command, and it also said this message (i thought i had tried it on
> linux but obviously not), OSX 10.6 running gimp 2.8.3 didnt give the
> same error message, and im sure windows 7 running gimp 2.8.6 (from
> memory) also didnt give the handler error.
>
>  From what little research that i have done since, the error is quite a
> complicated one. Something to do with data strips ending in FF D9 in a
> hex editor. The 0001 file has 3 of these, the other 2 that i have tried
> only have 1 reference (from searching the file).
>
> Ella's other suggestion for converting from jpg to png, i entered
> "convert DSC0002.jpg test.png" and it converted the image, with the
> corruption, with no error's reported, also tried dsc0001 and it
> converted fine (but the original image was ok).
>
> Im assuming meta data is not transfered to a PNG, ill be honest, i dont
> know much about them, as most of my work is saved back out as JPEG's
> etc, apart from when exporting from inkscape, which prefers PNG's/Tiffs
> etc.

Hmm, well, it does sound like file damage rather than just a case of 
messed up metadata or a version of jpeg that imagemagick can read and 
other image editors can't. Perhaps someone else can help. I don't know 
anything at all about recovering damaged image files.

If the thumbs are intact, this page:
http://ninedegreesbelow.com/photography/exiftool-commands.html#extract
tells how to use exiftool to extract the thumbnail as a separate image 
file. As always, work on a copy of the original.

Good luck!

Elle