high quality scaling in batch mode

[smalls]

hi,
(my iview version is 4.20 on win xp pro sp2)

i would like to scale a bunch of 10mpixel pictures into a small thumbnail format and another format appropriate for zoom-in-view on the internet. the point is:

i go to "file - batch conversion"
and under "batch conversion settings - options" i choose the highest quality (i.e. 100)
and i check the "use-advanced-options" check box and in the advanced options i choose the resize parameters and check the boxes
"preserve aspect ratio" and
"use resample function" (without this the results were pretty ugly)

finally i get good quality. but there are so many other options. is one of them supposed to even increase the quality (usual pictures with colors) ???

thanks

[Bhikkhu Pesala]

my iview version is 4.20 on win xp pro sp2

4.23 is the latest version. It is worth ugrading to get better zoom control among other improvements.

I choose the highest quality (i.e. 100)

To be honest, highest quality is probably wasted on the web. Try saving a sample image at a range of quality settings from 50 to 100, and do a blind test (i.e. not knowing which is which) to see if you can tell them apart. There is a difference, obviously, but the trade off with file size becomes unattractive above a setting of 75. For fast-loading web pages, smaller file size is better.

There are so many other options. is one of them supposed to even increase the quality (usual pictures with colors).

You probably don't need to adjust any other settings. Gamma correction might be useful if your images tend to be too dark or too light.

The subject matter of the photos is also an important factor. When you use JPG compression, sharply contrasting areas of colours result in artifacts, which is not a problem with soft edges. In brief, this means that you can get away with a much lower quality setting on photos of landscapes and people than you can with images of machines, buildings, or text.