diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c38d0657f..841b45f55 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -30,6 +30,10 @@ jobs:
     steps:
       - name: "Checkout code"
         uses: "actions/checkout@v7"
+      - name: "Pre-install system image libraries"
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libpng-dev libjpeg-dev libwebp-dev imagemagick
       - name: "Setup PHP"
         uses: "shivammathur/setup-php@v2"
         with:
diff --git a/src/mako/pixel/image/inspectors/imagemagick/ColorAt.php b/src/mako/pixel/image/inspectors/imagemagick/ColorAt.php
index 28fb0d2c5..34ebf7bb1 100644
--- a/src/mako/pixel/image/inspectors/imagemagick/ColorAt.php
+++ b/src/mako/pixel/image/inspectors/imagemagick/ColorAt.php
@@ -47,8 +47,13 @@ public function inspect(object &$imageResource): mixed
 
 		$pixel = $imageResource->getImagePixelColor($this->pixel->x, $this->pixel->y);
 
-		$rgba = $pixel->getColor(2); // 2 = RGBA normalized to 0-255
+		$color = $pixel->getColor(1);
 
-		return new Color($rgba['r'], $rgba['g'], $rgba['b'], $rgba['a']);
+		$r = (int) round($color['r'] * 255);
+		$g = (int) round($color['g'] * 255);
+		$b = (int) round($color['b'] * 255);
+		$a = (int) round($pixel->getColorValue(Imagick::COLOR_ALPHA) * 255);
+
+		return new Color($r, $g, $b, $a);
 	}
 }
diff --git a/src/mako/pixel/image/inspectors/imagemagick/TopColors.php b/src/mako/pixel/image/inspectors/imagemagick/TopColors.php
index bd3ae79f9..b92fcec59 100644
--- a/src/mako/pixel/image/inspectors/imagemagick/TopColors.php
+++ b/src/mako/pixel/image/inspectors/imagemagick/TopColors.php
@@ -53,13 +53,18 @@ public function inspect(object &$imageResource): mixed
 				break;
 			}
 
-			$rgba = $pixel->getColor(2); // 2 = RGBA normalized to 0-255
+			$color = $pixel->getColor(1);
 
-			if ($hasAlphaChannel && $this->ignoreTransparent && $rgba['a'] === 0) {
+			$r = (int) round($color['r'] * 255);
+			$g = (int) round($color['g'] * 255);
+			$b = (int) round($color['b'] * 255);
+			$a = (int) round($pixel->getColorValue(Imagick::COLOR_ALPHA) * 255);
+
+			if ($hasAlphaChannel && $this->ignoreTransparent && $a === 0) {
 				continue;
 			}
 
-			$colors[] = new Color($rgba['r'], $rgba['g'], $rgba['b'], $rgba['a']);
+			$colors[] = new Color($r, $g, $b, $a);
 		}
 
 		return $colors;
diff --git a/tests/unit/pixel/image/operations/imagemagick/ReplaceColorTest.php b/tests/unit/pixel/image/operations/imagemagick/ReplaceColorTest.php
index 99b99593d..bcf5d1dfa 100644
--- a/tests/unit/pixel/image/operations/imagemagick/ReplaceColorTest.php
+++ b/tests/unit/pixel/image/operations/imagemagick/ReplaceColorTest.php
@@ -36,7 +36,7 @@ public function testReplaceColors(): void
 
 		$image->apply(new ReplaceColor(
 			Color::fromHex('#0376BB'),
-			new Color(0, 0, 0)
+			new Color(0, 0, 0, 127)
 		));
 
 		$colors = $image->inspect(new TopColors);
@@ -44,6 +44,7 @@ public function testReplaceColors(): void
 		$this->assertCount(3, $colors);
 
 		$this->assertSame('#000000', $colors[0]->toHexString());
+		$this->assertSame('#0000007F', $colors[0]->toHexaString());
 		$this->assertSame('#B51700', $colors[1]->toHexString());
 		$this->assertSame('#047101', $colors[2]->toHexString());
 	}