diff --git a/SDWebImage/Core/SDImageIOAnimatedCoder.m b/SDWebImage/Core/SDImageIOAnimatedCoder.m
index f5d33a04..a543ac57 100644
--- a/SDWebImage/Core/SDImageIOAnimatedCoder.m
+++ b/SDWebImage/Core/SDImageIOAnimatedCoder.m
@@ -184,10 +184,10 @@ static CGImageRef SDImageIOPNGPluginBuggyCreateWorkaround(CGImageRef cgImage) CF
     CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(cgImage);
     CGImageAlphaInfo alphaInfo = (bitmapInfo & kCGBitmapAlphaInfoMask);
     CGImageAlphaInfo newAlphaInfo = alphaInfo;
-    if (alphaInfo == kCGImageAlphaPremultipliedLast) {
-        newAlphaInfo = kCGImageAlphaLast;
-    } else if (alphaInfo == kCGImageAlphaPremultipliedFirst) {
-        newAlphaInfo = kCGImageAlphaFirst;
+    if (alphaInfo == kCGImageAlphaLast) {
+        newAlphaInfo = kCGImageAlphaPremultipliedLast;
+    } else if (alphaInfo == kCGImageAlphaFirst) {
+        newAlphaInfo = kCGImageAlphaPremultipliedFirst;
     }
     if (newAlphaInfo != alphaInfo) {
         CGBitmapInfo byteOrderInfo = bitmapInfo & kCGBitmapByteOrderMask;
@@ -244,6 +244,8 @@ static BOOL SDImageIOPNGPluginBuggyNeedWorkaround(void) {
 #endif
             }
         }
+        CFRelease(source);
+        CGImageRelease(cgImage);
     });
     
     return isBuggy;
diff --git a/Tests/SDWebImage Tests.xcodeproj/project.pbxproj b/Tests/SDWebImage Tests.xcodeproj/project.pbxproj
index c5746e28..862d94a5 100644
--- a/Tests/SDWebImage Tests.xcodeproj/project.pbxproj	
+++ b/Tests/SDWebImage Tests.xcodeproj/project.pbxproj	
@@ -47,6 +47,9 @@
 		326E69482334C0C300B7252C /* TestLoopCount.gif in Resources */ = {isa = PBXBuildFile; fileRef = 326E69462334C0C200B7252C /* TestLoopCount.gif */; };
 		327054E2206CEFF3006EA328 /* TestImageAnimated.apng in Resources */ = {isa = PBXBuildFile; fileRef = 327054E1206CEFF3006EA328 /* TestImageAnimated.apng */; };
 		327054E3206CEFF3006EA328 /* TestImageAnimated.apng in Resources */ = {isa = PBXBuildFile; fileRef = 327054E1206CEFF3006EA328 /* TestImageAnimated.apng */; };
+		3278F5E22B04C1AC0004A6EE /* IndexedPNG.png in Resources */ = {isa = PBXBuildFile; fileRef = 3278F5E12B04C1AC0004A6EE /* IndexedPNG.png */; };
+		3278F5E32B04C1AC0004A6EE /* IndexedPNG.png in Resources */ = {isa = PBXBuildFile; fileRef = 3278F5E12B04C1AC0004A6EE /* IndexedPNG.png */; };
+		3278F5E42B04C1AC0004A6EE /* IndexedPNG.png in Resources */ = {isa = PBXBuildFile; fileRef = 3278F5E12B04C1AC0004A6EE /* IndexedPNG.png */; };
 		327A418C211D660600495442 /* TestImage.heic in Resources */ = {isa = PBXBuildFile; fileRef = 327A418B211D660600495442 /* TestImage.heic */; };
 		327A418D211D660600495442 /* TestImage.heic in Resources */ = {isa = PBXBuildFile; fileRef = 327A418B211D660600495442 /* TestImage.heic */; };
 		328BB6DD20825E9800760D6C /* SDWebImageTestCache.m in Sources */ = {isa = PBXBuildFile; fileRef = 328BB6DC20825E9800760D6C /* SDWebImageTestCache.m */; };
@@ -149,6 +152,7 @@
 		3264FF2E205D42CB00F6BD48 /* SDWebImageTestTransformer.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SDWebImageTestTransformer.m; sourceTree = "<group>"; };
 		326E69462334C0C200B7252C /* TestLoopCount.gif */ = {isa = PBXFileReference; lastKnownFileType = image.gif; path = TestLoopCount.gif; sourceTree = "<group>"; };
 		327054E1206CEFF3006EA328 /* TestImageAnimated.apng */ = {isa = PBXFileReference; lastKnownFileType = file; path = TestImageAnimated.apng; sourceTree = "<group>"; };
+		3278F5E12B04C1AC0004A6EE /* IndexedPNG.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = IndexedPNG.png; sourceTree = "<group>"; };
 		327A418B211D660600495442 /* TestImage.heic */ = {isa = PBXFileReference; lastKnownFileType = file; path = TestImage.heic; sourceTree = "<group>"; };
 		328BAF262240C08E00FC70DD /* Test-Shared.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; path = "Test-Shared.xcconfig"; sourceTree = "<group>"; };
 		328BAF272240C08E00FC70DD /* Test-Release.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; path = "Test-Release.xcconfig"; sourceTree = "<group>"; };
@@ -266,6 +270,7 @@
 			isa = PBXGroup;
 			children = (
 				32648066250232F7004FA0FC /* 1@2x.gif */,
+				3278F5E12B04C1AC0004A6EE /* IndexedPNG.png */,
 				433BBBBA1D7EFA8B0086B6E9 /* MonochromeTestImage.jpg */,
 				324047432271956F007C53E1 /* TestEXIF.png */,
 				3264CD162AAB1E23001E338B /* TestJFIF.jpg */,
@@ -497,6 +502,7 @@
 				329922892365DC6C00EAFD97 /* TestImageLarge.jpg in Resources */,
 				32648069250232F7004FA0FC /* 1@2x.gif in Resources */,
 				3299228A2365DC6C00EAFD97 /* TestImage.png in Resources */,
+				3278F5E42B04C1AC0004A6EE /* IndexedPNG.png in Resources */,
 				329922842365DC6C00EAFD97 /* MonochromeTestImage.jpg in Resources */,
 				329922882365DC6C00EAFD97 /* TestImage.jpg in Resources */,
 				32515F9E24AF1919005E8F79 /* TestImageAnimated.webp in Resources */,
@@ -524,6 +530,7 @@
 				32B99EA6203B31360017FD66 /* TestImage.png in Resources */,
 				32648068250232F7004FA0FC /* 1@2x.gif in Resources */,
 				3297A0A023374D1700814590 /* TestImageAnimated.heic in Resources */,
+				3278F5E32B04C1AC0004A6EE /* IndexedPNG.png in Resources */,
 				32B99EA2203B31360017FD66 /* MonochromeTestImage.jpg in Resources */,
 				32905E65211D786E00460FCF /* TestImage.heif in Resources */,
 				32515F9D24AF1919005E8F79 /* TestImageAnimated.webp in Resources */,
@@ -551,6 +558,7 @@
 				433BBBB71D7EF8200086B6E9 /* TestImage.gif in Resources */,
 				32648067250232F7004FA0FC /* 1@2x.gif in Resources */,
 				433BBBB91D7EF8260086B6E9 /* TestImage.png in Resources */,
+				3278F5E22B04C1AC0004A6EE /* IndexedPNG.png in Resources */,
 				3297A09F23374D1700814590 /* TestImageAnimated.heic in Resources */,
 				327054E2206CEFF3006EA328 /* TestImageAnimated.apng in Resources */,
 				32515F9C24AF1919005E8F79 /* TestImageAnimated.webp in Resources */,
diff --git a/Tests/Tests/Images/IndexedPNG.png b/Tests/Tests/Images/IndexedPNG.png
new file mode 100644
index 00000000..8ed105e1
Binary files /dev/null and b/Tests/Tests/Images/IndexedPNG.png differ
diff --git a/Tests/Tests/SDImageCoderTests.m b/Tests/Tests/SDImageCoderTests.m
index 50a70c47..acd70e70 100644
--- a/Tests/Tests/SDImageCoderTests.m
+++ b/Tests/Tests/SDImageCoderTests.m
@@ -558,6 +558,21 @@
     expect(exifOrientation).equal(kCGImagePropertyOrientationDown);
 }
 
+- (void)test30ThatImageIOPNGPluginBuggyWorkaround {
+    // See: #3634
+    NSURL *url = [[NSBundle bundleForClass:[self class]] URLForResource:@"IndexedPNG" withExtension:@"png"];
+    NSData *data = [NSData dataWithContentsOfURL:url];
+    
+    UIImage *decodedImage = [SDImageIOCoder.sharedCoder decodedImageWithData:data options:nil];
+    UIColor *testColor1 = [decodedImage sd_colorAtPoint:CGPointMake(100, 1)];
+    CGFloat r1, g1, b1, a1;
+    [testColor1 getRed:&r1 green:&g1 blue:&b1 alpha:&a1];
+    expect(r1).beCloseToWithin(0.60, 0.01);
+    expect(g1).beCloseToWithin(0.91, 0.01);
+    expect(b1).beCloseToWithin(0.91, 0.01);
+    expect(a1).beCloseToWithin(0.20, 0.01);
+}
+
 #pragma mark - Utils
 
 - (void)verifyCoder:(id<SDImageCoder>)coder