CloudinaryURLBuilder.swift

import UIKit

final class CloudinaryURLBuilder {

    // MARK: - Properties
    
    private let source: URL
    
    // MARK: -
    
    private var width: Int?
    private var height: Int?
    
    // MARK: - Initialization

    init(source: URL) {
        self.source = source
    }

    // MARK: - Public API
    
    func width(_ width: Int) -> CloudinaryURLBuilder {
        self.width = width
        
        return self
    }
    
    func height(_ height: Int) -> CloudinaryURLBuilder {
        self.height = height
        
        return self
    }
        
    func build() -> URL {
        var parameters: [String] = []
        var url = Environment.cloudinaryBaseUrl

        if let width = width {
            parameters.append("w_\(width)")
        }
        
        if let height = height {
            parameters.append("h_\(height)")
        }
        
        // Define Format
        parameters.append("f_png")
        
        // Define Device Pixel Ratio
        let dpr = String(format: "%1.1f", UIScreen.main.scale)
        parameters.append("dpr_\(dpr)")
        
        // Append Parameters
        if !parameters.isEmpty {
            let parametersAsString = parameters.joined(separator: ",")
            url = url.appendingPathComponent(parametersAsString)
        }
        
        return url.appendingPathComponent(source.absoluteString)
    }

}

This is how you would use the CloudinaryURLBuilder class.

CloudinaryURLBuilder(source: episode.thumbnailUrl)
    .width(200)
    .build()