(09-04-2022, 04:25 PM)hsmokey Wrote: Thanks so much for replies and suggestions- Tried both and the compression/quality at 85 brings the document down to about 9 MB- Better, but still much larger than the other sample document of the same dimensions. Still not sure why Gimp seems to export the JPG's in a way that takes up so much space! Would really like it to take up the same, smaller amount of space as other documents I have of the same dimensions-
You have to know the compression ratio of the images you compare with. There are several applications that can do this.
For instance using ImageMagick identify command:
identify -format "Quality: %[quality] - Chroma subsampling: %[jpeg:_sampling-factor]\n" image.jpg
Yields:
Quality: 95 - Chroma subsampling: 2x1,1x1,1x1
There are several ways to denote the chroma-subsampling (they are detailed here) but the important thing isto check if the Gimp-generated files and your other files are using the same settings.
Note: remove the _ in jpeg:_sampling-factor. I had to add it to prevent semi-colon+s to be translated into a smiley.