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One way to quickly guestimate if the file can be repaired is by looking at 'entropy'. We checked and found the file does contain data, now what can be a next step? Now assume we can not open the JPEG, for example the software tells you "It looks like we don't support this file format". Most likely symptom for a corrupt header is the inability to open the JPEG at all. Exception is the section that contains the image data, it's size is not defined, it should be decoded until we reach an end of image marker.Īlthough there may not be officially something that can be called the header, I refer to all section apart from the section containing the actual image data as header. Each section starts with a ' marker' which tells the purpose of the section and it's size. If I know of a free tool that can be tried for a certain repair I will mention that too! I will refrain from linking to my own software.īasically JPEG is a set of sections, some of which we could consider meta data and one, the largest the actual image data. If and how depends and I'll explain using software I use and wrote, JPEG-Repair to repair JPEGs. If this is actually what you see, nothing can repair the files. I often get sent JPEGs for repair, and I estimate files are zero-filled in at least 50% of cases. Verify the files are not filled with zeros of some repeating byte pattern (FF FF FF etc.). Spot check some of the files using a hex editor, HxD is free. So, to anyone reading this in the future: As far as we know the file may be filled with zeros. This is an often made, incorrect assumption. Each file is approx 3MB, so there must be plenty of data to This is another highly acclaimed software that did not work for me. Unfortunately, the files are too large to upload. This is an online service that again got rave reviews. I'm not really sure what to do with this error message. WARNING: Unknown marker, stopping decode When I use this software, I get the following error message: Start Offset: 0x00000000 They are from my uncles camera, so it would mean a lot to him if I could get them fixed. Each file is approx 3MB, so there must be plenty of data to work with. They were all taken from the same camera.