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piau9000 · 02-02-2018, 12:09 PM

Hi. I'm facing some problems with image quality for quite some time and I can't find what may be causing it.

Somehow, when I add a epub file to calibre, it converts some images from PNG to JPG and then back to PNG. You can cleary see it as it generates all the usual garbage that JPG adds (around texts for example it looks like literal puke).

Also it seems to affect only cover images. The other ones are not touched.

What is causing it?
The PNG inside the original epub is perfect as I compared it pixel by pixel with the source. But the PNG inside the epub on the calibre folder is clearly JPG.
I'm not talking about the small JPG file on the same folder, as it is indeed a lower quality JPG. I'm talking about the one inside the epub file.

Is there a way to make it stop?

02-02-2018, 12:09 PM	#1
piau9000 Junior Member Posts: 3 Karma: 10 Join Date: Feb 2018 Device: none	PNG images losing quality. Hi. I'm facing some problems with image quality for quite some time and I can't find what may be causing it. Somehow, when I add a epub file to calibre, it converts some images from PNG to JPG and then back to PNG. You can cleary see it as it generates all the usual garbage that JPG adds (around texts for example it looks like literal puke). Also it seems to affect only cover images. The other ones are not touched. What is causing it? The PNG inside the original epub is perfect as I compared it pixel by pixel with the source. But the PNG inside the epub on the calibre folder is clearly JPG. I'm not talking about the small JPG file on the same folder, as it is indeed a lower quality JPG. I'm talking about the one inside the epub file. Is there a way to make it stop?