More help with color changes

[rinaldop]

I have 15 images that go from this 
   
to this 
   
middle like this 
   
and finally to this 
   

I want to change the colors from orange and black to blue and purple. Is there an easy way to do this perhaps in BIMP or is there a way to create these images from scratch? I see them used as temperature gauges in many pc stat displays like here.

https://www.pcsense.neit/kore/

Thanks!