diff --git a/libvips/foreign/spngload.c b/libvips/foreign/spngload.c
index 319eafb2..05e33070 100644
--- a/libvips/foreign/spngload.c
+++ b/libvips/foreign/spngload.c
@@ -275,6 +275,7 @@ vips_foreign_load_png_header( VipsForeignLoad *load )
 
 	int flags;
 	int error;
+	struct spng_trns trns;
 
 	/* In non-fail mode, ignore CRC errors.
 	 */
@@ -354,6 +355,23 @@ vips_foreign_load_png_header( VipsForeignLoad *load )
 		return( -1 );
 	}
 
+	if( !spng_get_trns( png->ctx, &trns ) ) {
+		if( png->ihdr.color_type == SPNG_COLOR_TYPE_TRUECOLOR ) {
+			if( png->ihdr.bit_depth == 16 ) 
+				png->fmt = SPNG_FMT_RGBA16;
+			else 
+				png->fmt = SPNG_FMT_RGBA8;
+		}
+		else if( png->ihdr.color_type == SPNG_COLOR_TYPE_INDEXED ) 
+			png->fmt = SPNG_FMT_RGBA8;
+		else if( png->ihdr.color_type == SPNG_COLOR_TYPE_GRAYSCALE ) {
+			if( png->ihdr.bit_depth == 16 ) 
+				png->fmt = SPNG_FMT_GA16;
+			else 
+				png->fmt = SPNG_FMT_GA8;
+		}
+	}
+
 	if( png->ihdr.bit_depth == 16 ) {
 		png->format = VIPS_FORMAT_USHORT;
 		if( png->interpretation == VIPS_INTERPRETATION_B_W )