Question by Roxy_Chic: Fix Damaged Images AFTER Data Recovery Has Been Performed?
I used a data recovery program to recover lost images from my digital camera. Unfortunately some of them came out grey. Meaning, when I look at the picture as a thumbnail, I can see the entire picture, but when I open the image, a large portion of it completely greyed out. Any idea of how I can fix these images? I’ve tried recovering them twice and both times the same images came out damaged.
Answer by What?
The photos are damaged. The embedded thumbnails appear fine because they were pre-generated. Think about it like a lock and key: if one tooth of a key is missing, it’ll still fit but it won’t unlock the door. Recovery may be possible but only if you know what you’re doing.
Here’s how one person capable of preforming these recoveries describes the condition:
” – Grey Areas in your Image
In various forums on the internet, people have incorrectly stated that photos are unrecoverable if they contain gray areas. This is not usually true. Some JPEG decoders are very picky with how they recover from errors and simply report Drawing Failed (in Windows Picture and Fax Viewer), while others might draw a middle-gray region or just display a “Red X”. In some cases the gray area is in fact completely damaged (overwritten by unrelated data), but this is not always the case.
– Why do JPEGs get damaged?
There are many sources of damage to photo files, but the most common reasons are:
– Photos were deleted or formatted & a “recovery” utility was used
– Memory card / hard drive error (logical or physical error)
– RAM failure
– File transfer / interface error (memory coherency issues, buffer over/underrun, etc.)
– What Happens when you Open / Decode a Corrupted JPEG?
Even a single byte changed in a JPEG file can cause an image to be unrecognizable (or not open at all). Why? Because of the way JPEG compression is designed, images are stored in tightly-packed streams of binary bits (not bytes). Each pixel can be represented by as few as 2 bits to as many as 26 bits (dictated by the variable-length Huffman Coding scheme). To make matters worse, in an effort to keep the compression as efficient as possible, there is virtually nothing to indicate where you are in the stream of bits (unless Restart Markers are used). Therefore, as soon as a single bit is encountered wrong, the millions of bits that follow will be decoded incorrectly as well. The manner in which DC and AC coefficients are arranged in MCUs means that this corruption often shows up in shearing, wild color shifts and many other visual phenomena.”
It appears from the examples and comments that he or she is fully capable of preforming JPEG recovery when such operation is possible. Unfortunately, the author no longer accepts recovery requests.
There are similar JPEG recovery services available but your photos should be worth the cost. Here’s one example (I don’t know the reputation of the company so I can’t recommend it):
The company above seems to recover a small number of JPEG submissions for free for their own analysis and your benefit.
There are a number of recovery tools available too, but unless those pictures are very important they aren’t worth the money; you don’t know for sure if the files are recoverable, but mostly because you’ll only have the programmers word that it even works.
Know better? Leave your own answer in the comments!