Example code for "how to share image on Facebook, Instagram, Whatsapp and Activity" with Swift 4+

ShareImageOnSocialMedia.swift

/* Common steps to use these codes */
// 1- you need to implement FBSharekit for sharing on Facebook
// 2- Copy and Paste the following text to your "info.plist" (anywhere)

/*
	<key>FacebookAppID</key>
	<string>08760425023140553</string> //This is a mock id, you must add your own real app id else it never will work
	<key>FacebookDisplayName</key>
	<string>DoYourBest</string> //Add your real app name here
	<key>LSApplicationQueriesSchemes</key>
	<array>
		<string>whatsapp</string>
		<string>instagram</string>
		<string>fbapi</string>
		<string>fb-messenger-share-api</string>
		<string>fbauth2</string>
		<string>fbshareextension</string>
	</array>
*/

import FBSDKShareKit

class ShareHelper: NSObject  {

    static func shareImageViaWhatsapp(image: UIImage, onView: UIView) {
        let urlWhats = "whatsapp://app"
        if let urlString = urlWhats.addingPercentEncoding(withAllowedCharacters:CharacterSet.urlQueryAllowed) {
            if let whatsappURL = URL(string: urlString) {
                
                if UIApplication.shared.canOpenURL(whatsappURL as URL) {
                    
                    guard let imageData = image.pngData() else { debugPrint("Cannot convert image to data!"); return }
                    
                    let tempFile = URL(fileURLWithPath: NSHomeDirectory()).appendingPathComponent("Documents/whatsAppTmp.wai")
                    do {
                        try imageData.write(to: tempFile, options: .atomic)
                        self.documentInteractionController = UIDocumentInteractionController(url: tempFile)
                        self.documentInteractionController.uti = "net.whatsapp.image"
                        self.documentInteractionController.presentOpenInMenu(from: CGRect.zero, in: onView, animated: true)
                        
                    } catch {
                        self.callAlertView(title: NSLocalizedString("information", comment: ""),
                                           message: "There was an error while processing, please contact our support team.",
                                           buttonText: "Close", fromViewController: topViewController!)
                        return
                    }
                    
                } else {
                    self.callAlertView(title: NSLocalizedString("warning", comment: ""),
                                       message: "Cannot open Whatsapp, be sure Whatsapp is installed on your device.",
                                       buttonText: "Close", fromViewController: topViewController!)
                }
            }
        }
    }
    
    static func shareImageViaInstagram(image: UIImage, onView: UIView) {
        let urlWhats = "instagram://app"
        if let urlString = urlWhats.addingPercentEncoding(withAllowedCharacters:CharacterSet.urlQueryAllowed) {
            if let whatsappURL = URL(string: urlString) {
                
                if UIApplication.shared.canOpenURL(whatsappURL as URL) {
                    
                    guard let imageData = image.pngData() else { debugPrint("Cannot convert image to data!"); return }
                    
                    let tempFile = URL(fileURLWithPath: NSHomeDirectory()).appendingPathComponent("Documents/fitbestPhoto.igo")
                    do {
                        try imageData.write(to: tempFile, options: .atomic)
                        self.documentInteractionController = UIDocumentInteractionController(url: tempFile)
                        self.documentInteractionController.uti = "com.instagram.exclusivegram"
                        self.documentInteractionController.presentOpenInMenu(from: CGRect.zero, in: onView, animated: true)
                        
                    } catch {
                        self.callAlertView(title: NSLocalizedString("information", comment: ""),
                                           message: "There was an error while processing, please contact our support team.",
                                           buttonText: "Close", fromViewController: topViewController!)
                        return
                    }
                    
                } else {
                    self.callAlertView(title: NSLocalizedString("warning", comment: ""),
                                       message: "Cannot open Instagram, be sure Instagram is installed on your device.",
                                       buttonText: "Close", fromViewController: topViewController!)
                }
            }
        }
    }
    
    static func shareImageViaFacebook(image: UIImage, fromViewController: UIViewController) {
        
        let sharePhoto = FBSDKSharePhoto()
        sharePhoto.image = image
        sharePhoto.isUserGenerated = true
        
        let content = FBSDKSharePhotoContent()
        content.photos = [sharePhoto]
        
        let dialog = FBSDKShareDialog()
        dialog.delegate = (fromViewController as! FBSDKSharingDelegate)
        dialog.fromViewController = fromViewController
        dialog.shareContent = content
        dialog.mode = .shareSheet
        dialog.show()
    }
    
    static func shareImageViaActivity(image: UIImage, onView: UIViewController) {
        let vc = UIActivityViewController(activityItems: [image], applicationActivities: [])
        // so that iPads won't crash
        if UtilitiesHelper.deviceModel().contains("iPad") {
            if let popoverController = vc.popoverPresentationController {
                popoverController.sourceView = onView.view
                popoverController.sourceRect = CGRect(x: onView.view.bounds.midX, y: onView.view.bounds.maxY, width: 0, height: 0)
                popoverController.permittedArrowDirections = []
            }
        }
        
        // exclude some activity types from the list (optional)
        onView.present(vc, animated: true)
        
    }
}