How do I make an image grey scale

[mzamo]

I'm trying to add images to my app whose colour I can change, I saw on the guides that this is done with grey scale images. But how do i do this. I tried those online grey scale converters but it didn't work. Help.

[LekoFraggle · Accepted solution]

I ended up using the application they recommended.  I have Photoshop, but that did not seem to work.  So, I created the image I wanted, then I ran the recommended code...

convert original.png -colorspace gray final.png

Through ImageMagick.  That did the trick.