Drastic increase in file size with libvips versions after v8.12.2

[KJ1i]

Hello,

I am writing to report an issue with libvips versions beyond v8.12.2.

Problem:

After processing an image, such as this zipped one input.zip, using libvips versions newer than v8.12.2, there is a bug causing a drastic increase in the file size of the output image.

Example:

• In v8.15.0, the size of the image is escalated from 18.2 MB to 31.7 MB.
• Conversely, in v8.12.2, the increase is comparatively modest, going from 18.2 MB to 19.1 MB.

Test Command Used:

vips copy input.png output.png

Steps to Reproduce:

1. Download the above zipped image file.
2. Use the vips copy command as specified above with versions v8.12.2 and v8.15.0.
3. Observe the resulting file sizes of the output images.

Expected Result:

The file size should remain relatively stable across libvips versions, as observed between v8.12.2 and v8.15.0.

Thank you for your time and assistance.

[lovell]

Please see #2929 - you'll need to specify filter=all for the same behaviour as v8.12.2.

[KJ1i]

Thanks for the quick reply.