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If the editor decided to publish this info using EXIF like Paint.NET in this example:
Tools like JPEGsnoop can try guess what camera or editor was used to create the file.
Few words about corruption
I don't know how this will help solve the corruption problem. Some tool corrupting the JPEGs IMO is unlikely. I repair JPEGs as a service and I don't recall ever seeing corruption that makes me suspect a specific tool. For example the grey band you refer to is frequently due to bit flips.
A program bug would perhaps produce reproducible damage and corruption. You should be able to extract a pattern of some kind probably. What you describe does not seem to suggest that.
A single bitflip can cause this type of corruption but far more often I see a larger area (say few hundred to few thousand bytes being corrupt). Some times the corruption looks random so hard to determine what caused it, but it also occurs I see a complete sector inside the corrupt file that is in fact part of a FAT directory (which could for example suggest file system corruption rather than file corruption).
A single bitflip inside encoded image data can do this:
Bad Peggy may be right after all ..
Tools like Bad Peggy are not uncommonly producing false positives as well as false negatives and thus can not be relied upon for a final judgement as to whether a file is corrupt or not.
It's also important to recognize the fact some image viewers open a file based on their contents rather than extension, and so it's well possible that a PNG with a JPEG or JPG extension is correctly identified by Bad Peggy as non-JPEG while your image viewer has no trouble opening it. For example a PNG with incorrect JPG extension will open just fine using a tool like ImageGlass.
