Sharing ScreenShot on WhatsApp using iOS Activity Popup

I have trouble sharing the screenshot of my game in WhatsApp.  Facebook works fine but WhatsApp doesn’t show the image in the message. This is my code;

local items = {     { type = "image", value = { filename = "screenCap.png", baseDir = system.DocumentsDirectory } },     { type = "string", value = "Hello!" }, } local function showShare()     local popupName = "activity"     local isAvailable = native.canShowPopup( popupName )     local isSimulator = "simulator" == system.getInfo( "environment" )          -- Capture the screen     if(screenCap) then         screenCap:removeSelf();     end     screenCap = display.captureScreen()        screenCap.x = display.contentCenterX     screenCap.y = display.contentCenterY     display.save(screenCap,"screenCap.png")     screenCap:toBack()     -- If it is possible to show the popup     if isAvailable then         local listener = {}         function listener:popup( event )             print( "name(" .. event.name .. ") type(" .. event.type .. ") activity(" .. tostring(event.activity) .. ") action(" .. tostring(event.action) .. ")" )         end                  -- Show the popup         native.showPopup( popupName,         {             items = items,             -- excludedActivities = { "UIActivityTypeCopyToPasteboard", },             listener = listener,             origin = buttonshare.contentBounds,             permittedArrowDirections={ "up", "down" }         })     else         if isSimulator then             native.showAlert( "Build for device", "This plugin is not supported on the Corona Simulator, please build for an iOS/Android device or the Xcode simulator", { "OK" } )         else             -- Popup isn't available; show error message             native.showAlert( "Error", "Can't display the view controller. Are you running iOS 7 or later?", { "OK" } )         end     end   end