Change color of png in buttons – ios

Following code will set tint colour for normal state of button:

For Swift 4 and newer:

let origImage = UIImage(named: "imageName")
let tintedImage = origImage?.withRenderingMode(.alwaysTemplate)
btn.setImage(tintedImage, for: .normal)
btn.tintColor = .red

You can change tint colour according to your need when state changes for button.

Older versions

For Swift 3:

let origImage = UIImage(named: "imageName")
let tintedImage = origImage?.withRenderingMode(.alwaysTemplate)
btn.setImage(tintedImage, forState: .normal)
btn.tintColor = .redColor

For Swift 2:
see revision history.