diff --git a/modules/juce_graphics/image_formats/juce_PNGLoader.cpp b/modules/juce_graphics/image_formats/juce_PNGLoader.cpp
index 172868661f..bf126092c8 100644
--- a/modules/juce_graphics/image_formats/juce_PNGLoader.cpp
+++ b/modules/juce_graphics/image_formats/juce_PNGLoader.cpp
@@ -254,6 +254,9 @@ namespace pnglibNamespace
   #define PNG_LINKAGE_FUNCTION
 
   #define PNG_ARM_NEON_OPT 0
+  #define PNG_POWERPC_VSX_OPT 0
+  #define PNG_INTEL_SSE_OPT 0
+  #define PNG_MIPS_MSA_OPT 0
 
   #if ! defined (PNG_USER_WIDTH_MAX)
    #define PNG_USER_WIDTH_MAX 1000000