diff --git a/wp-content/themes/twentynineteen/sass/blocks/_blocks.scss b/wp-content/themes/twentynineteen/sass/blocks/_blocks.scss
index 72822b1263..7c843a13c6 100644
--- a/wp-content/themes/twentynineteen/sass/blocks/_blocks.scss
+++ b/wp-content/themes/twentynineteen/sass/blocks/_blocks.scss
@@ -505,20 +505,40 @@
 
 	//! Image
 	.wp-block-image {
+		max-width: 100%;
 
 		img {
 			display: block;
 		}
 
-		&.alignleft,
-		&.alignright {
-			max-width: 100%;
+		.aligncenter {
+			
+			@include postContentMaxWidth();
+
+			@include media(tablet) {
+				margin: 0;
+				width: $size__site-tablet-content;
+
+				img {
+					margin: 0 auto;
+				}
+			}
+
+			@include media(desktop) {
+				width: $size__site-desktop-content;
+
+				img {
+					margin: 0 auto;
+				}
+			}
 		}
 
 		&.alignfull img {
 			width: 100vw;
+			max-width: calc( 100% + (2 * #{$size__spacing-unit}));
 
 			@include media(tablet) {
+				max-width: calc( 125% + 150px );
 				margin-left: auto;
 				margin-right: auto;
 			}
diff --git a/wp-content/themes/twentynineteen/style-rtl.css b/wp-content/themes/twentynineteen/style-rtl.css
index c5ca35cdd5..f4569a3f30 100644
--- a/wp-content/themes/twentynineteen/style-rtl.css
+++ b/wp-content/themes/twentynineteen/style-rtl.css
@@ -3944,20 +3944,53 @@ body.page .main-navigation {
   }
 }
 
+.entry .entry-content .wp-block-image {
+  max-width: 100%;
+}
+
 .entry .entry-content .wp-block-image img {
   display: block;
 }
 
-.entry .entry-content .wp-block-image.alignleft, .entry .entry-content .wp-block-image.alignright {
-  max-width: 100%;
+@media only screen and (min-width: 768px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    max-width: calc(8 * (100vw / 12) - 28px);
+  }
+}
+
+@media only screen and (min-width: 1168px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    max-width: calc(6 * (100vw / 12) - 28px);
+  }
+}
+
+@media only screen and (min-width: 768px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    margin: 0;
+    width: calc(8 * (100vw / 12) - 28px);
+  }
+  .entry .entry-content .wp-block-image .aligncenter img {
+    margin: 0 auto;
+  }
+}
+
+@media only screen and (min-width: 1168px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    width: calc(6 * (100vw / 12) - 28px);
+  }
+  .entry .entry-content .wp-block-image .aligncenter img {
+    margin: 0 auto;
+  }
 }
 
 .entry .entry-content .wp-block-image.alignfull img {
   width: 100vw;
+  max-width: calc( 100% + (2 * 1rem));
 }
 
 @media only screen and (min-width: 768px) {
   .entry .entry-content .wp-block-image.alignfull img {
+    max-width: calc( 125% + 150px);
     margin-right: auto;
     margin-left: auto;
   }
diff --git a/wp-content/themes/twentynineteen/style.css b/wp-content/themes/twentynineteen/style.css
index 6d593e38f1..c10e8701b2 100644
--- a/wp-content/themes/twentynineteen/style.css
+++ b/wp-content/themes/twentynineteen/style.css
@@ -3956,20 +3956,53 @@ body.page .main-navigation {
   }
 }
 
+.entry .entry-content .wp-block-image {
+  max-width: 100%;
+}
+
 .entry .entry-content .wp-block-image img {
   display: block;
 }
 
-.entry .entry-content .wp-block-image.alignleft, .entry .entry-content .wp-block-image.alignright {
-  max-width: 100%;
+@media only screen and (min-width: 768px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    max-width: calc(8 * (100vw / 12) - 28px);
+  }
+}
+
+@media only screen and (min-width: 1168px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    max-width: calc(6 * (100vw / 12) - 28px);
+  }
+}
+
+@media only screen and (min-width: 768px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    margin: 0;
+    width: calc(8 * (100vw / 12) - 28px);
+  }
+  .entry .entry-content .wp-block-image .aligncenter img {
+    margin: 0 auto;
+  }
+}
+
+@media only screen and (min-width: 1168px) {
+  .entry .entry-content .wp-block-image .aligncenter {
+    width: calc(6 * (100vw / 12) - 28px);
+  }
+  .entry .entry-content .wp-block-image .aligncenter img {
+    margin: 0 auto;
+  }
 }
 
 .entry .entry-content .wp-block-image.alignfull img {
   width: 100vw;
+  max-width: calc( 100% + (2 * 1rem));
 }
 
 @media only screen and (min-width: 768px) {
   .entry .entry-content .wp-block-image.alignfull img {
+    max-width: calc( 125% + 150px);
     margin-left: auto;
     margin-right: auto;
   }
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 5d73be06ab..fa0a819744 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44370';
+$wp_version = '5.1-alpha-44371';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.