Override clearing of img borders in wp-admin by core

packages/block-library/src/image/style.scss

@@ -97,6 +97,42 @@
 			border-radius: 0;
 		}
 	}
+
+	// The following is required to overcome WP Core applying styles that clear
+	// img borders with a higher specificity than those added by the border
+	// block support to provide a default border-style of solid when a border
+	// color or width has been set.
+	:where(.has-border-color) {
+		border-style: solid;
+	}
+	:where([style*="border-top-color"]) {
+		border-top-style: solid;
+	}
+	:where([style*="border-right-color"]) {
+		border-right-style: solid;
+	}
+	:where([style*="border-bottom-color"]) {
+		border-bottom-style: solid;
+	}
+	:where([style*="border-left-color"]) {
+		border-left-style: solid;
+	}
+
+	:where([style*="border-width"]) {
+		border-style: solid;
+	}
+	:where([style*="border-top-width"]) {
+		border-top-style: solid;
+	}
+	:where([style*="border-right-width"]) {
+		border-right-style: solid;
+	}
+	:where([style*="border-bottom-width"]) {
+		border-bottom-style: solid;
+	}
+	:where([style*="border-left-width"]) {
+		border-left-style: solid;
+	}
 }
 
 .wp-block-image figure {