fix image links

Author: jvns

cookbook/A quick tour of IPython Notebook.ipynb

@@ -73,17 +73,17 @@
    "source": [
     "After the first time, you should see this:\n",
     "<div align=\"center\">\n",
-    "<img src=\"files/images/tab-once.png\" width=\"75%\">\n",
+    "<img src=\"images/tab-once.png\" width=\"75%\">\n",
     "</div>\n",
     "\n",
     "After the second time:\n",
     "<div align=\"center\">\n",
-    "<img src=\"files/images/tab-twice.png\" width=\"75%\">\n",
+    "<img src=\"images/tab-twice.png\" width=\"75%\">\n",
     "</div>\n",
     "\n",
     "After the fourth time, a big help box should pop up at the bottom of the screen, with the full documentation for the `read_csv` function:\n",
     "<div align=\"center\">\n",
-    "<img src=\"files/images/tab-4-times.png\" width=\"90%\">\n",
+    "<img src=\"images/tab-4-times.png\" width=\"90%\">\n",
     "</div>"
    ]
   },
@@ -112,7 +112,7 @@
     "You should see this:\n",
     "\n",
     "<div align=\"center\">\n",
-    "<img src=\"files/images/function-completion.png\" width=\"30%\">\n",
+    "<img src=\"images/function-completion.png\" width=\"30%\">\n",
     "</div>"
    ]
   },