I was using Windows 7. I had run a test and had determined that I had a bunch of damaged JPG image files. Apparently this could happen sometimes when files were saved on a CD or other drive with an iffy file table. In my case, it did not help to try to open the files in question on a different computer. It was also not a case of recovering data from a damaged memory card, for which a tool like ZAR digital image recovery might be needed. This was a situation of already having the files on the hard drive, but not being able to view them. So: how to repair them?
One possibility was to buy PixRecovery for $50. They had a demo version, so I downloaded and tried that. I had used Bulk Rename Utility to rename the corrupted JPGs so that their names ended with " - corrupted" without a JPG extension so that I would be able to pull them out if any of them got mixed with good JPGs. But unlike IrfanView, PixRecovery was not able to detect them until they did have a JPG extension, so I had to rename them back again. PixRecovery did not appear to be able to process the JPGs in bulk; I would have to fix them one at a time. On the first one I tried, I got "No data to recover detected." They did give me an option to "order a paid file review" for $199 per file. I tried another file. The program didn't remember the output directory I had just specified for the first one, so I had to trace back through the directory structure to find it again. This time, I got a message, "Recovered with demo restrictions." It didn't show me the actual picture, though, even with a watermark or stamp on it; it just showed me a JPG saying, "The image has been repaired in demo mode by PixRecovery." So I couldn't verify that the picture was fully restored; I would just have to take their word for it until I paid and tried it. PixRecovery also gav me a Corrupted Data Analysis Report for the "restored" photo, with a statement of recoverability (i.e., Low, Average, or Good). This seemed like something they could have provided on a batch basis for all files -- at least in the paid version, if not in the free -- so that the user would not have to go through the manual steps for each photo regardless of recoverability.
Among sites offering to provide a file examination for a fee, VG Jpeg-Repair offered an online service that would evaluate up to 100MB of JPGs for 1 Euro. Alternately, it sounded like the user could pay them 20 Euros and get an evaluation of an entire set of JPGs, and then pay around $1 per JPG for the ones that they could repair. I didn't investigate this too closely at this point; this just seemed to be the general idea. I recalled seeing other pay-per-file sites, but didn't look into those either at this stage. An eHow article pointed toward several other data recovery services, including Ontrack Data Recovery, Total Recall Data Recovery and ACE Data Group. Previous exposure and brief examination of these sites suggested that they were more oriented toward recovering data from damaged drives, though no doubt they could recover photos too -- but that they could be very expensive.
I found a review of Jpeg Repair Picture Doctor ($100) that made it sound like software to avoid, in the sense that it could trash good photos and pretend that it had restored bad ones. On the other hand, it apparently had a batch process and a trial phase, so if there was a good backup, it seemed like a way of possibly reducing the number of corrupted JPGs to restore. Another review said that the best JPG repair option was to use PhotoRescue. It looked like it was for recovering lost data from drives, not for JPG repair. They offered Wizard 3.1 for everyone ($29), Expert 2.1 for power users ($29), and Advanced 2.1 for ultimate experts ($99). I tried the Expert 2.1 demo. It was indeed oriented toward recovering drives. I couldn't figure out how to use it for fixing JPGs.
Another program, JPEG Recovery Pro ($50), seemed to be offering a 15-day trial that would at least show me low-quality watermarked copies of the photos after recovery. They also had a Basic version ($40), but it seemed to lack some features that would be useful when editing numerous JPGs. I downloaded and tried their Pro version. When I ran it, I got an error: "Access violation at address 00846DC1 in module 'JPEGRec5.exe." Possibly it was due to the fact that I installed without first shutting down all other programs. I uninstalled and tried again. That wasn't it. I tried on a different folder. It worked. Apparently the file and folder name combination was too long. I moved the folder to a higher-level location, so that the full pathname would be shorter, and tried again. Nope. I removed spaces from the folder name. No. I made the folder name shorter than 9 characters. No. I removed the files from that folder to another high-level folder with an eight-character name. Still got the error. I put a copy of one of the corrupted JPGs in a different folder. The program ran on that folder, in the sense of detecting several JPGs there, but it did not detect this particular JPG. So, hmm, this program was a possibility, but I'd have to tinker with it to make it work.
There may have been other possibilities. I did not fully explore the results of my search. But at this point it did start to seem that, if I wanted to download a program and do my own file recovery, it appeared that it would have to be a manual, one-by-one recovery process, whether using PixRecovery or some other program. I ran across references to JPEGsnoop and other programs that likewise seemed to require the user to do bit-by-bit editing of the JPG file in ways that were sometimes described as difficult. It appeared that JPEGsnoop might provide a relatively easy way to locate where the errors were.
I looked at the corrupted JPGs in IrfanView again. For the ones I looked at, the error was the same: "Can't read file header! Unknown file format or file not found!" I did a search and found people going through various struggles. One suggestion was to try opening the corrupted JPGs in a different image editing program. IrfanView was often recommended, but these had already failed there, so now I tried Gimp. It allowed me to select and try opening all of the corrupted JPGs. None opened, so Gimp did not seem superior to IrfanView in this task. Gimp did, however, produce more detailed error messages. It showed only the first several onscreen and then redirected the rest of them to stderr. I wasn't sure where that was. The several that did appear onscreen indicated that several files had similar problems: "starts with 0x31 0xd9" or "starts with "0xaa 0xe9." These seemed to mean I would have to edit the files manually to correct those starting errors. Microsoft said that stderr meant the command prompt window. It seemed I could capture the full log of errors by starting Gimp from the command line and redirecting that output to a text file. Right-clicking > Properties on the Gimp icon that I clicked on to run the program told me where the Gimp .exe file was. I opened a command window there and typed the needed command. I was running the portable version of Gimp, so in my case the command was:
start "" "W:\Start Menu\Programs\Multimedia\Images\Editors\GIMPPortable\GimpPortable.exe" > D:\GimpLog.txtSo then, when Gimp started, I tried again to open all those JPGs. When Gimp was done trying and failing, I opened D:\GimpLog.txt. Unfortunately, there was nothing in it, so apparently I hadn't done that quite right.
I still didn't have a plan for what I would do if I did find out exactly what the errors were, so I paused the error output project to think about that. I decided that these were old files, and there was really no urgency to this project. There was always the possibility that, in the next year or however long it would be until I would get back to it, someone would come along with a cheap or free program or other great solution that would really take care of it, without all that manual editing. Therefore, I shelved this project for the time being.