diff --git a/modules/juce_graphics/native/juce_mac_CoreGraphicsContext.mm b/modules/juce_graphics/native/juce_mac_CoreGraphicsContext.mm
index 4de9851f61..a847a1fdd5 100644
--- a/modules/juce_graphics/native/juce_mac_CoreGraphicsContext.mm
+++ b/modules/juce_graphics/native/juce_mac_CoreGraphicsContext.mm
@@ -36,7 +36,7 @@ public:
         pixelStride = format == Image::RGB ? 3 : ((format == Image::ARGB) ? 4 : 1);
         lineStride = (pixelStride * jmax (1, width) + 3) & ~3;
 
-        imageData.allocate ((size_t) (lineStride * jmax (1, height)), clearImage);
+        imageData.allocate ((size_t) lineStride * (size_t) jmax (1, height), clearImage);
 
         CGColorSpaceRef colourSpace = (format == Image::SingleChannel) ? CGColorSpaceCreateDeviceGray()
                                                                        : CGColorSpaceCreateDeviceRGB();
@@ -112,13 +112,13 @@ public:
 
         if (mustOutliveSource)
         {
-            CFDataRef data = CFDataCreate (0, (const UInt8*) srcData.data, (CFIndex) (srcData.lineStride * srcData.height));
+            CFDataRef data = CFDataCreate (0, (const UInt8*) srcData.data, (CFIndex) ((size_t) srcData.lineStride * (size_t) srcData.height));
             provider = CGDataProviderCreateWithCFData (data);
             CFRelease (data);
         }
         else
         {
-            provider = CGDataProviderCreateWithData (0, srcData.data, (size_t) (srcData.lineStride * srcData.height), 0);
+            provider = CGDataProviderCreateWithData (0, srcData.data, (size_t) srcData.lineStride * (size_t) srcData.height, 0);
         }
 
         CGImageRef imageRef = CGImageCreate ((size_t) srcData.width,