Util needed to convert JPG to Transparent PNG

I require a small utility program that can look at a folder path, read each JPG file 1 by 1, and convert each JPG to Transparent PNG files. Each JPG will have 1 colour that can be swapped to Transparent.

So the utility should allow me to specify the RGB or Hex value of the colour in the JPG to treat as the transparent.

For example I have a JPG where RGB 000000 (black) is the background, and I want all RGB 000000 to be converted to transparent in the PNG output file.

The program should be able to operate on a folder of JPGs and process them all.

The program can be Windows/DOS command line or windows forms.