October 7th, 2002, 05:26 AM
ImageMagick: Too large files
I use the following ImageMagick command to resize a 1600x1200 jpeg image to a 200x150 jpeg:
convert -size 200x150 -geometry 200x150 large.jpg thumb.jpg
The thumb file is about 22 kB.
If I use an image editor like Paint Shop Pro, I'm able to reduse the same file (large.jpg) to a 200x150 jpeg which is not more than about 4 kB.
Why is the ImageMagick file so large? Is it possible to reduse the file size?
October 7th, 2002, 01:36 PM
-quality 80 eg would reduce file size (and quality!)
October 8th, 2002, 06:07 AM
Imagemagick: Quality doesn't reduse size
The documentation says that the default value of -quality is 75, but I tried to set the quality to different lower values. But that didn't decrease the file size either.
I found out something else, though:
If the image was 800x600 in the first place - in stead of 1600x1200 - then the 200x150 thumb was only 8 kB.
I have also tried the +profile '*', but it doesn't seem to help...
Is convert the right application? What about mogrify?
October 8th, 2002, 12:22 PM
Hmm. I donīt know. I always use convert and it does a great job. One thing i noticed:
Many functions donīt work on WinNT/2000. Or they donīt work as expected.
eg. i could not make thumbnails with 24bit jpegs on Windows. it always dropped the palette and i got funny kinda psychedelic looking thumbs.
No problems at all on linux, filesize is fine... (i only have used 640x480 as max. input format)
Are you running linux or windows? And do you have the newest release of IM?
if you canīt get it fixed another way, try to convert down to eg. 320x200 first (100% quality) and then convert again down to your thumbīs size.