colored-jpg to grayscale-jpg

Hi, I am new here,

 

I tried to convert a colored „jpg“ raster image to „grayscale".

 

Until now i used the programm „IrfanView“, where I set the saturation-value to „-255“,

 

but i had to do it for every image seperatly.

 

Now I want to use FME for conversion of multiple pictures at once.

 

Could you help me to find the correct transformer for this work?

 

Or is there any other simply way to convert a various number of colored jpeg images into grayscale?

 

Thanks for answers ……