chore: remove unused historic image files

fix_missing_spaces.py

@@ -0,0 +1,66 @@
+import os
+import re
+
+def process_file(filepath):
+    try:
+        with open(filepath, "r", encoding="utf-8") as f:
+            lines = f.readlines()
+    except Exception as e:
+        print(f"Error reading {filepath}: {e}")
+        return
+
+    in_code_block = False
+    in_frontmatter = False
+    changed = False
+
+    for i in range(len(lines)):
+        line = lines[i]
+        
+        # Checking for yaml frontmatter
+        if i == 0 and line.strip() == "---":
+            in_frontmatter = True
+            continue
+        if in_frontmatter and line.strip() == "---":
+            in_frontmatter = False
+            continue
+        if in_frontmatter:
+            continue
+        
+        # Checking for code block
+        if line.strip().startswith("```"):
+            in_code_block = not in_code_block
+            continue
+            
+        if not in_code_block:
+            # We want to find lines like:
+            # -foo
+            # -**bold**
+            # Match optional whitespace, then a single dash, then something not space, not -, not <
+            m = re.match(r'^(\s*)-([^\s\-<].*)$', line)
+            if m:
+                # To distinguish from command line arguments like -p or -v which might legitimately appear outside code blocks 
+                # (though usually they shouldn't), let's be careful. The user specifically asked to fix all list symbols -.
+                # We will just insert a space.
+                new_line = m.group(1) + "- " + m.group(2) + "\n"
+                lines[i] = new_line
+                changed = True
+
+    if changed:
+        try:
+            with open(filepath, "w", encoding="utf-8") as f:
+                f.writelines(lines)
+            print(f"Fixed: {filepath}")
+        except Exception as e:
+            print(f"Error writing {filepath}: {e}")
+
+count = 0
+for root, dirs, files in os.walk("/Users/baohua/Github/books/docker_practice"):
+    # ALWAYS modify dirs in-place to prevent os.walk from entering them
+    dirs[:] = [d for d in dirs if d not in (".git", "node_modules", "dist", "build")]
+    
+    for file in files:
+        if file.endswith(".md"):
+            process_file(os.path.join(root, file))
+
+print("Done fixing.")
+