Polish Books deletes image

[BobC]

Downloaded Calibre 2.46 (X64) and ran Polish Books on a book that was reasonably heavy on images with the intention of cutting down the image sizes:

This is a partial result :

OEBPS/html/images/pub.jpg compressed from 19.8 KB to 5.4 KB bytes [72.4% reduction]
OEBPS/html/images/FPlate14.jpg compressed from 112.7 KB to 80.3 KB bytes [28.8% reduction]
OEBPS/html/images/FPlate12.jpg compressed from 107.9 KB to 72.6 KB bytes [32.7% reduction]
OEBPS/html/images/FPlate28.jpg compressed from 117.7 KB to 0 B bytes [100.0% reduction]
OEBPS/html/images/FPlate4.jpg compressed from 136.8 KB to 100.2 KB bytes [26.8% reduction]
OEBPS/html/images/SPlate10.jpg compressed from 129 KB to 97.3 KB bytes [24.6% reduction]
OEBPS/html/images/SPlate11.jpg compressed from 92.3 KB to 65.4 KB bytes [29.1% reduction]
OEBPS/html/images/FPlate29.jpg compressed from 114.4 KB to 80.6 KB bytes [29.5% reduction]
OEBPS/html/images/SPlate24.jpg compressed from 127.6 KB to 94.5 KB bytes [25.9% reduction]

Note in particular FPlate28.jpg compressed down to zero.

I compared the two books (original and polished copy) and sure enough the image, which showed up perfectly in the original was now empty.

I assume there is some peculiarity in the original image but compressing to zero seems excessive, an error trap to retain the original image would seem sensible. I know I can restore the original EPUB but then I lose all the compression on all the other images.

Anyone else noted this ?

BobC

[kovidgoyal]

Can you attach the image. From the log it looks like a jpeg image, calibre uses the mozjpeg compressor for that, it's likely a bug in that, but I need the image to be sure.

[BobC]

I'd rather not post it -can I PM it or email you a copy ?

[kovidgoyal]

You can use the calibre bug tracker to attach files, bugs can be marked private.