Image regress tests.

regress/image-common.inc

@@ -0,0 +1,10 @@
+# Check server image support. Exit 101 to tell the runner to skip this test.
+image_check_support()
+{
+	support=$("$@" display-message -p '#{image_support}') || exit 1
+	case "$support" in
+	1) return ;;
+	0) exit 101 ;;
+	*) echo "unexpected image_support: $support" >&2; exit 1 ;;
+	esac
+}