Tint Color Not Applying to Saved PNG Image in Swift

Question

I'm working on an iOS app in Swift where I need to save a PNG image with a tint color applied. However, I'm facing an issue where the tint color doesn't seem to apply to the saved image as expected.

Here's the relevant part of my Swift code:

func saveOutputImageAsPNG() {
        guard let outputImage = signature else {
            return
        }
        
        // Create a UIImage with the selected background color
        let coloredImage = outputImage.withTintColor(UIColor(bgColor), renderingMode: .alwaysTemplate)
        
        if let pngData = coloredImage.pngData() {
            // Choose a file URL to save the PNG image.
            // You can modify this path as per your requirements.
            if let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first {
                let dateFormatter = DateFormatter()
                dateFormatter.dateFormat = "yyyy_MM_dd_HHmmss"
                
                // Get the current date and time as a string in the specified format
                let currentDateTime = dateFormatter.string(from: Date())
                let fileURL = documentsDirectory.appendingPathComponent("\(currentDateTime)_signature.png")
                
                do {
                    try pngData.write(to: fileURL)
                    print("Saved as PNG: \(fileURL)")
                } catch {
                    print("Error saving PNG: \(error)")
                }
            }
        }
    }

Despite setting the tint color (bgColor), the saved PNG image doesn't reflect this color change. I've double-checked that bgColor is correctly set.

Can anyone help me understand why the tint color isn't being applied to the saved PNG image and suggest a solution to achieve the desired result?