add test

Tests/DownTests/Styler/ImageStyleTests.swift

@@ -0,0 +1,30 @@
+//
+//  ImageStyleTests.swift
+//  
+//
+//  Created by Mikhail Ivanov on 25.05.2021.
+//
+
+#if os(iOS)
+
+class ImageStyleTests: StylerTestSuite {
+
+    /// # Important
+    ///
+    /// Snapshot tests must be run on the same simulator used to record the reference snapshots, otherwise
+    /// the comparison may fail. These tests were recorded on the **iPhone 12** simulator.
+    ///
+
+    func testThat_Image_IsStyled() {
+        // Given
+        let markdown = """
+        Checking the loading of the image: ![cat](https://stihi.ru/pics/2021/01/23/1043.jpg)
+        """
+
+        // Then
+        assertStyle(for: markdown, width: .narrow)
+    }
+
+}
+
+#endif