Does batch/change color depth work?

[yky]

I have several images with a size around 3.2 Mb. I want to reduce their size. I tried batch/change color depth and set it to 256 colors (8 BPP). The resulting image size was 2.7 Mb. However, image information showed there were 16.7 Million colors. I also tried Custom colors and set it to 256. Still, the resulting images had 16.7 million colors.

I then manually reduced color depth of one image and saved it. Same result. The saved file had 16.7 million colors.

I also notice that when overwriting the existing files, the date/time is not changed. The date/time of the replaced file, not the replacing file, is kept. So, I cannot tell when the file is overwritten.

This is version 4.42 (32 bit) on Windows 8.1.

[Bhikkhu Pesala]

What file format are you using? JPG are always 24-bit, unless you save as grayscale.

IIRC, if you're saving Exif data, then the creation date is taken from that.

[jazzman]

...I also notice that when overwriting the existing files, the date/time is not changed. The date/time of the replaced file, not the replacing file, is kept. So, I cannot tell when the file is overwritten. ...

see here: