not perfect, but cleaner

assets/sass/_theme/blocks/image.sass

@@ -56,7 +56,6 @@
                         display: block
                         text-align: right
             &.image-landscape
-                
                 picture
                     margin-left: -$grid-gutter
                     margin-right: -$grid-gutter
@@ -67,5 +66,8 @@
                     display: flex
                     justify-content: space-between
                     align-items: baseline
+                    *
+                        flex: 1 1
                     .credit
-                        margin-top: 0
\ No newline at end of file
+                        margin-top: 0
+                        text-align: right
\ No newline at end of file