(11 hours ago)estatistics Wrote: Same JPG picture with 100% quality in GIMP, and saving all information, without any other processing
a) Saving it as WEBP, result half size.
b) Running mogrify -quality 100 -format webp on same JPG picture, double size resulted.
Why? What is doing GIMP and what is doing IM6 mogrify when transforming JPG to webp format?
Note that the differences in picture quality between JPG and gimp 100% webp and im6 100% webp in full zoom are almost not visible.
I am not sure what you are trying to demonstrate. The English term is, Comparing Apples with Pears.
As downloaded your image is 1.6 MB (the comment says CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 90)
Uncompresssed image (as a tiff) 36 MB
Exporting from Gimp
100 quality jpeg 3.7 MB
100 quality webp 1.6 MB
lossless webp 5.3 MB
...different compression formats (jpeg/webp) will give different results, that is expected.
When it comes to exporting webp at various compression settings (no metadata) Gimp and Imagemagick are roughly the same file size.
Quote:Because i have GIMP 3, is lacking scipt-fu in menu (why?)
using bash, i try to make all jpg to be saved as webp. How?
gimp -i --verbose -b '(let* (file-webp-save 1 image drawable "$webp_name" "$webp_name" 0 $lossless $quality 100.0 1 1 1 0 0 0 0 67 0))' --batch-interpreter="plug-in-script-fu-eval"
What OS are you using For Gimp 3.0 ? Is it possible to run that command line ?
Gimp 3 script-fu is not exactly the same syntax as Gimp 2.10
If you revert to Gimp 2.10 then the BIMP plugin will convert to .webp