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It doesn't seem to matter what program I re-save an image with or in what format, it always comes out with a lower quality/contrast/brightness version. I really can't figure out why.

Original sample:

enter image description here

Re-saved in Paint Windows 7 / Photoshop CS5 / IrfanView (Same result from all 3):

enter image description here

(I did a hash check to confirm that the upload is the same file as uploaded from my PC)

Animated GIF between the two to make the difference obvious:

enter image description here

It does not matter if I save it as PNG, JPEG, BMP, etc... I get the same lower-quality result.

Any idea why this is happening?

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Thanks for the clean-up, Gareth – WhiteZero Apr 28 '11 at 5:10
Could this be a driver-level issue? – WhiteZero Apr 28 '11 at 12:19
I saved the same image on my Windows 7 work PC using MSpaint in the same fashion I did at home, and it looks fine. So this is definitely an issue local only to my home PC. – WhiteZero Apr 28 '11 at 13:26
A co-worked pointed out that maybe with Photoshop, Adobe installed some sort of gamma-correction service that might be causing this. I'll look into this when I get home. – WhiteZero Apr 28 '11 at 13:31
Nothing from Adobe seems to be be running that might cause this. I suppose I could try Safe Mode anyway... – WhiteZero Apr 30 '11 at 14:48
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4 Answers

up vote 0 down vote

Can you resave it using photoshop CS5? since you seem to have it as per your question.

If you want to compress your image, use the save for web wizard (File - Save for Web) and then toggle to the 4view. In that view you can audition your images before saving them. Try out the different formats listed there.

EDIT : I tried it out for you and there is hardly any change even though I have saved the picture down. Take a look.

Here I saved this to a jpeg format (high) in the save for web wizard (387 KB)

saved to jpeg

Here is your original image: (737 KB) enter image description here

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Yes, that is what I meant in my original post when I said "(Windows 7) / Photoshop CS5 / IrfanView". I can save it in all 3 programs and the output is exactly the same as was pictured. I can save as PNG, JPEG, BMP, doesn't matter... I get the same result. – WhiteZero Apr 28 '11 at 11:34
well i happened to save it and that's what I got. Did you use save for web? – rzlines Apr 28 '11 at 11:43
No, but I'll try that when I get home. Though "save for web" is going to skew the issue, because that applies compression. My point in the OP is that I can re-save an image with no compression, and I get a lower quality image. This should not happen. – WhiteZero Apr 28 '11 at 13:19
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up vote 0 down vote accepted

Ok, I think this must have been my video driver. I notice the problem is gone since I moved to nvidia driver 285.38

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up vote -1 down vote

Can you see anything in the "Save File" dialog about colour depth? It looks like that is the problem to me!

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When saving in Photoshop I can select the "Depth" of the picture. But changing this setting has no effect on this issue. In MSPaint, when saving as a 24-bit BMP, you cannot choose depth, and the picture comes out the same. – WhiteZero Apr 28 '11 at 12:18
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up vote -1 down vote

Why save the same image again? You can just use copy-paste. I think any decent image-aware software was write in that way. When saving "again" they are trying to build a file in the target format independent of the input format.

What is tricky is about PNG giving lower results. PNGs are using lossless compression method (i.e. compression without losing information) and shouldn't giving any lower-quality image, remember file can change (compression!).

Think about that and do some research about lossless and lossy compression methods. Do the PNG saving again and check just to be sure.

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Sorry, but telling someone to fix their issue by not even trying is just silly. I'm not just saving images for the fun of it, but rather using that as an example of my issue. Also, it's not just PNG's, as noted in my OP. – WhiteZero Aug 1 '11 at 2:30
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