Photos app adds jpeg compression

Photos app adds compression

I noticed that when I watch a photo using the Metro Photos app, there is a jpeg compression applied to the photo that degrades the image quality. When I watch the very same photo using the Windows Picture Viewer, no compression is added and the image quality is not decreased. See the images below; left is the image seen in Windows Photo Viewer and right as seen in the Photos app. Do you also experience this behavior Is there a way to turn off the compression that the Photos app adds? Because it is starting to become very annoying.

Well the compression is already there in the source image. The viewer is certainly not adding any MORE compression before displaying it.

I think that what is happening is that the compression that is already there is becoming a lot more obvious/visible due to the way its being displayed. The photo app may be adding sharpening (best guess looking at those samples) or it may be adding some contrast or something in an attempt to make them look better to the casual viewer.

It's definately NOT a good thing though

Well, I doubt that the Photo app is only sharpening the image (and enhancing the global contrast perhaps). I definitely see some compression (I'm quite sure it's not just that the already available compression is sharpened, but that additional compression is added as well). To make a clearer comparison, I increased the contrast in both images. You can then very clearly see that additional compression is added (the fine(r) structures in the left image (especially in the sky) are replaced by more blocky structures in the right image, and also notice the compression block at the right of the dark triangular shape in the bottom half of the image). So it's not just sharpening compression artifacts that were already present.

Well all post processing removes color and detail.

Not sure the exact issue but could be any number of things, color/contrast enhancement, sharpening, running through an ICC engine. All of those would remove smooth gradations particularly in the bright areas.

Or I suppose it could /possibly/ be just a crappier jpeg decompressor than the normal viewer but that would be strange...

I just cant see the viewer uncompressing the image, then recompressing it, then uncompressing it again for display (Course that wouldn't be the only insane thing MS did in Windows 8 so who knows really!)

Yes, there could indeed be a lot of post processing steps that degrade the quality. In these examples I only showed a particular cropped section of the entire photo. Overall, when I compare the entire photo using the Windows Photo Viewer and the Photos app, the image quality of the Photos app is worse; it is duller and not as sharp as the Windows Photo viewer. So whatever 'post processing' steps the Photos app is applying, they are certainly not improving the perceived quality, but definitely degrading the image quality compared to the Windows Photo Viewer.

I don't know, but maybe a reason for adding compression could be to ensure a smooth scrolling/swiping experience on all these Windows tablets, as the performance could decrease when the large, original images are used.

Still remains the question, can one turn off the post processing in the Photos app? :huh: