Added a test for transparent images

Author: NicoWeio

tests/test_graphical_units/control_data/img_and_svg/ImageTransparency.npz

@@ -252,6 +252,21 @@ def test_ImageMobject(scene):
     scene.wait(1)
 
 
+@frames_comparison
+def test_ImageTransparency(scene):
+    file_path = get_svg_resource("translate.png")
+    im1 = ImageMobject(file_path).scale(5)
+    im2 = ImageMobject(file_path, invert=True).scale(5).shift(1 * LEFT + 2 * DOWN)
+    im3 = ImageMobject(file_path).scale(5).shift(1 * RIGHT + 2 * UP)
+
+    im1.set_opacity(0.5)
+    im2.set_opacity(0.5)
+    im3.set_opacity(0.5).set_color(RED)
+
+    scene.add(im1, im2, im3)
+    scene.wait()
+
+
 @frames_comparison
 def test_ImageInterpolation(scene):
     img = ImageMobject(