CLI tool for Scale2x?

[Zucca]

I would like to have some kind of CLI image resizer that uses Scale2x algorithm, or Scale4x.


I currently have been working on a nice CLI utility that converts already Scale2x'd images to bigger size and smooths them.
I also pay attention to image size in disk. So I already use some kind of tools to optimize those images to png image format format.
This tool I'm working, is mainly targeted to screen shots taken from 4-16-bit games.
Currently I'm using Hermit-filter to resize screen shots from 400% size to 200% size, but that method creates more colors and isn't good when compressing images. Normally screenshots from these games consist maxium of 64 colors and with Scale2x colors won't increase, but with Hermit they will . And that's why I would like to know if any of you can point me a good image scaler that won't add more colors to an image.

EDIT: Currently I can produce quite nice 128-colour png screenshots. However the colorspace is still reduced.
Anyway here's one 24-bit (16777216 colour) image as an example hi-quality screenshot. The low quality will not have as many colors as this image. I'm targetting to 64 to 256 -color image.

EDIT2: There's a for of Scale2x called SuperScale2x. It's bit better than Scale2x and it offers also a possibility for antialiasing (that I don't need in this case). But I couldn't find any source code to compile or even any binaries. ;(

[Zucca]

Ok. I finally decided to download Scale2x sources from sf.net.
I compiled the source because there were few cli tools for converting png's. They wotk pretty ok. :) Now I can do Scale2x, Scale3x and Scale4x resizing. Altough Scale4x is just two times Scale2x. Only Scale3x differs. It actually uses a bit different algorithm.

I'll be working on some test shots soon (on another topic).
I still would like to test SuperScaleX2. So if anyone finds sources, please post a reply. :)