How do I do this

[regulus]

I'm looking for an app/easy way to change the colour of screenshots I took on my iPhone.

For example, my FaceTime Recent Calls list display a black background. If I take a screenshot and try and print it, the background prints in black. I want it to be white in order to save ink. I've tried taking a screenshot whilst Inverting colours, still black.

Hope this makes sense

 

[bloodiedathame]

Put it in an image editor such as Photoshop or Gimp and invert the colours there and save.