save the pictures!
February 17, 2006 4:19 PM   Subscribe

My camera recently ate a month's worth of intense picture-taking! About 90% were salvaged by imgsave, but of course the remaining 10% are the best or most important. Each of those broken images completely draws as a thumbnail, but only partially renders when opened. There is no apparent consistency to how much is drawn or which pictures were eaten.

The camera is an Olympus Stylus 600, the flash card is an Olympus xD-Picture card 512 MB (MXD512MB, it says on the back). I have an image of the card as-is. All metadata seems to be gone (e.g. date). Help?

Opinions on whether this is the fault of the camera, card, or the xD-PCMCIA card used to transfer them are also welcome - they are all new.
posted by whatzit to Technology (9 answers total) 1 user marked this as a favorite
 
Response by poster: hmph. apparently the program that saved most of my day is saveimg not imgsave. Thanks for any suggestions to come...
posted by whatzit at 4:21 PM on February 17, 2006


Try connect the camera to your pc thru USB and read them from there, or, try a different card.
posted by doctor_negative at 5:25 PM on February 17, 2006


er, connecting
posted by doctor_negative at 5:26 PM on February 17, 2006


Find someone with a Mac and use File Juicer. It hasn’t let me down yet. I’ve used it to recover image files, essays I didn’t make a hard copy of, license numbers I forgot to write down, etc.
posted by Yeomans at 5:44 PM on February 17, 2006


Err, Sorry:
File Juicer

posted by Yeomans at 5:46 PM on February 17, 2006 [1 favorite]


I had a bunch of pictures get eaten off a memory stick once, only an hours worth, but they were pictures of a riot. Not something that happens too often.


Anyway, after that, I've always copied pictures by connecting the camera directly, rather then swapping cards, just too much risk of corruption while yanking it in and out.
posted by delmoi at 8:11 PM on February 17, 2006


Response by poster: I'm with you delmoi: I try not to pull out the cards, but there was no other choice this time. I'll try out the File Juicer and follow up on this later...
posted by whatzit at 8:53 PM on February 17, 2006


Best answer: Thanks to my local data recovery and all around technical guru we - no he - worked out a way to get them back. The following should be enough to give anyone else who has this problem and the knowledge a chance. All this recovery was done under Linux:

saveimg worked great for the pictures that were contiguous. The problem was with photos that were fragmented on the card. To recover these I needed to learn more about FAT16.

After reading Wikipedia on FAT and looking through a hexdump of the card, I began to understand how the data was laid out on the card.

Note that this card was not recognized as FAT16 by either windows or linux. Windows just wanted to format the card.

Taking what whatzit considered the most important broken image, I set out to reconstruct it. First I grepped through a hexdump of the card and generated a list of addresses at which the images started. These were in the same order as the images generated by saveimg, so I now had a mapping of image to starting address on the card. Working out address to FAT cluster I now had a place to look in the File Allocation Tables and find the next fragment.

(The "FAT" in a FAT filesystem is a table you index with a cluster number to find the next cluster in the file.)

The first picture I recovered had only two fragments, and I had the first one on hand as saveimg had recovered it. Looking at the FAT I found the second fragment and extracted it to a file with dd, then appended it to the first fragment. The picture was once again whole.

After doing this by hand for eight pictures I wrote a program to do it for me given a card image, an image of the FAT (which I had to correct in this case), a start address, and an output filename. The rest of the images were trivial to recover after that.
posted by whatzit at 8:35 PM on February 18, 2006


whatzit do you still have the recipie for bocado de principe? :( i tried your post and the link is dead
posted by Jowito at 2:46 PM on December 28, 2006


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