There is actually a simple explanation for this! The portion of the photo with bernie has been compressed more! Thus pushing it to the minimum error level. Think of it like this- each time a photo is reuploaded or resaved it goes through a compression process, unless it is saved in a lossless format. Eventually the photo cannot be compressed anymore, this is the minimum error level. The most telling thing here is that the most recent edit and compression event to any portion of the photo IS the clock area.
I don't think that's quite accurate. Jpeg compresses images by breaking the image up into small boxes, and then for each box, finding a set of weights to use to sum a set of known reference images such that the sum approximates the original box. Storing those weights takes up a lot less space than the individual pixels.
If you save an image as jpeg and then re-save it again without modification, the image won't degrade much after the first save because all the information that couldn't be represented as a sum of weighted reference images is gone, and what's left is the data that can be accurately represented as those weights.
If you manipulate the image, though, such as change the resolution or shift pixels around, the resulting bitmap may lose information again when converted to a jpeg. Also, if you take a highly compressed image, modify it, and then save it with a higher quality compression setting, the modified area will have more "information" in it than the rest of the image.
Well, that could be true. The more important thing to understand is the source image for the bernie portion has probably been uploaded, saved, shared etc before they even added him to the photo at all. It's hard to know the specifics here. What we can say for sure is that the clock area has seen, by far, fewer compression events.
There is actually a simple explanation for this! The portion of the photo with bernie has been compressed more! Thus pushing it to the minimum error level. Think of it like this- each time a photo is reuploaded or resaved it goes through a compression process, unless it is saved in a lossless format. Eventually the photo cannot be compressed anymore, this is the minimum error level. The most telling thing here is that the most recent edit and compression event to any portion of the photo IS the clock area.
It depends on many stuffs, not just compression, in this case you can spot Bernie much easier than the clock: https://snipboard.io/VQtqh6.jpg
i' trying to see if there's anything hidden within pixels...
awesome! although I don't think in this case you are looking at error levels. Is this looking at channels?
I don't think that's quite accurate. Jpeg compresses images by breaking the image up into small boxes, and then for each box, finding a set of weights to use to sum a set of known reference images such that the sum approximates the original box. Storing those weights takes up a lot less space than the individual pixels.
If you save an image as jpeg and then re-save it again without modification, the image won't degrade much after the first save because all the information that couldn't be represented as a sum of weighted reference images is gone, and what's left is the data that can be accurately represented as those weights.
If you manipulate the image, though, such as change the resolution or shift pixels around, the resulting bitmap may lose information again when converted to a jpeg. Also, if you take a highly compressed image, modify it, and then save it with a higher quality compression setting, the modified area will have more "information" in it than the rest of the image.
Well, that could be true. The more important thing to understand is the source image for the bernie portion has probably been uploaded, saved, shared etc before they even added him to the photo at all. It's hard to know the specifics here. What we can say for sure is that the clock area has seen, by far, fewer compression events.