Index: wp-content/themes/twentyseventeen/assets/css/editor-style.css
===================================================================
--- wp-content/themes/twentyseventeen/assets/css/editor-style.css	(revision 58682)
+++ wp-content/themes/twentyseventeen/assets/css/editor-style.css	(working copy)
@@ -579,3 +579,7 @@
 .rtl .mejs-offscreen {
 	right: -10000px;
 }
+
+.wp-block-image a img{
+	box-shadow: none;
+}
\ No newline at end of file
Index: wp-content/themes/twentyseventeen/style.css
===================================================================
--- wp-content/themes/twentyseventeen/style.css	(revision 58682)
+++ wp-content/themes/twentyseventeen/style.css	(working copy)
@@ -4375,3 +4375,7 @@
 		padding: 0;
 	}
 }
+
+.wp-block-image a img{
+	box-shadow: none;
+}
\ No newline at end of file