comparing the data from two images

[minty2b]

I am comparing the data of two separate different images, everything for the two matches:
File, JFIF, ICC-header, ICC_Profile and Composite.

The rest of the information has been stripped. The jpg quantization tables and structure are identical on both.

I also have a third image that has not been edited which matches the other two edited images with the same Image Width, Image Height, Encoding Process, Bits Per Sample, Color Components and Y Cb Cr Sub Sampling.

Would you say it was fair to suspect they were taken and edited by the same person using the same device/program?

[StarGeek]

Not really.

Things like the jpg quantization tables can be used to possibly identify the software used, but it's not uniquely identifiable to a specific installation.  Possibly to a specific camera, but a lot of programs use the same basic code from the original Independent JPEG Group code.

Take a look at the JPEGDigest tag.  It's not extracted by default, so you have to specifically extract it or use the -API RequestAll option .  You can also look at the JPEGDigest.pm source code to see the full list.

The lack of metadata is pretty meaningless.  Many websites strip away most identifiable metadata.  Some will also recompress uploaded images to save space, which will change the above JPEGDigest, most likely to whatever code that ImageMagick uses.  The other tags you mention, other than size, will rarely, if ever, differ from jpeg to jpeg.