I compress an image to JPEG format using a quality factor. I again use the newly compressed image and again compress it using same quality factor.
Every time result is different.
Is there any threshold where compression will stop? Or will it continue to compress previously compressed image? (Keeping same quality factor throughout)
I would recommend reading up on Lossy compression. Specifically:
The original contains a certain amount of information; there is a lower limit to the size of file that can carry all the information. As an intuitive example, most people know that a compressed ZIP file is smaller than the original file, but repeatedly compressing the file will not reduce the size to nothing and will in fact usually increase the size.
Also, from my understanding, it makes sense that the results are not repeatable. If the compression was repeatable (aka deterministic), that would mean it would be reversible, which would make it a lossless compression, which JPEG is not.
