Merge branch 'U4-8588' of https://github.com/JimBobSquarePants/Umbraco-CMS into JimBobSquarePants-U4-8588

# Conflicts:
#	build/NuSpecs/UmbracoCms.Core.nuspec
#	src/Umbraco.Web.UI/packages.config

src/Umbraco.Core/Logging/ImageProcessorLogger.cs

@@ -0,0 +1,46 @@
+namespace Umbraco.Core.Logging
+{
+    using System;
+    using System.Runtime.CompilerServices;
+
+    using ImageProcessor.Common.Exceptions;
+
+    /// <summary>
+    /// A logger for explicitly logging ImageProcessor exceptions.
+    /// <remarks>
+    /// Creating this logger is enough for ImageProcessor to find and replace its in-built debug logger
+    /// without any additional configuration required. This class currently has to be public in order 
+    /// to do so.
+    /// </remarks>
+    /// </summary>
+    public sealed class ImageProcessorLogger : ImageProcessor.Common.Exceptions.ILogger
+    {
+        /// <summary>
+        /// Logs the specified message as an error.
+        /// </summary>
+        /// <typeparam name="T">The type calling the logger.</typeparam>
+        /// <param name="text">The message to log.</param>
+        /// <param name="callerName">The property or method name calling the log.</param>
+        /// <param name="lineNumber">The line number where the method is called.</param>
+        public void Log<T>(string text, [CallerMemberName] string callerName = null, [CallerLineNumber] int lineNumber = 0)
+        {
+            // Using LogHelper since the ImageProcessor logger expects a parameterless constructor.
+            var message = string.Format("{0} {1} : {2}", callerName, lineNumber, text);
+            LogHelper.Error<T>(string.Empty, new ImageProcessingException(message));
+        }
+
+        /// <summary>
+        /// Logs the specified message as an error.
+        /// </summary>
+        /// <param name="type">The type calling the logger.</param>
+        /// <param name="text">The message to log.</param>
+        /// <param name="callerName">The property or method name calling the log.</param>
+        /// <param name="lineNumber">The line number where the method is called.</param>
+        public void Log(Type type, string text, [CallerMemberName] string callerName = null, [CallerLineNumber] int lineNumber = 0)
+        {
+            // Using LogHelper since the ImageProcessor logger expects a parameterless constructor.
+            var message = string.Format("{0} {1} : {2}", callerName, lineNumber, text);
+            LogHelper.Error(type, string.Empty, new ImageProcessingException(message));
+        }
+    }
+}