docs: add a plot with a WCS at the end

examples/11_Extracting_information_from_the_view.ipynb

@@ -26,6 +26,7 @@
     "from astroquery.simbad import Simbad\n",
     "from astroquery.vizier import Vizier\n",
     "import matplotlib.pyplot as plt\n",
+    "import numpy as np\n",
     "\n",
     "from ipyaladin import Aladin"
    ]
@@ -255,7 +256,8 @@
    "source": [
     "## Saving the view as an image file\n",
     "\n",
-    "In `save_view_as_image`, the first argument is the path to the file, the second is the format (\"png\", \"jpeg\", \"webp\"), and the third is a boolean to indicate if you want to include the Aladin Lite logo in the image."
+    "`save_view_as_image` takes a screenshot of the widget. The first argument is the path where the file should be written, the second is the format (\"png\", \"jpeg\", \"webp\"), and the third is a boolean to indicate if you want to include the Aladin Lite logo in the image. \n",
+    "These data are reflecting the pixels on the screen. For scientific use cases, opt for `get_view_as_fits` that is a bit longer since it retrieves the actual survey from a server."
    ]
   },
   {
@@ -265,6 +267,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "screenshot_wcs = aladin.wcs\n",
     "aladin.save_view_as_image(path=\"./crab.png\", image_format=\"png\", with_logo=True)"
    ]
   },
@@ -278,6 +281,28 @@
     "img = plt.imread(\"./crab.png\")\n",
     "plt.imshow(img)"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "dde7fe44",
+   "metadata": {},
+   "source": [
+    "And with the WCS that we stored at the same time than the screenshot"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "89d8f226",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "img = plt.imread(\"./crab.png\")\n",
+    "plt.subplot(projection=screenshot_wcs)\n",
+    "plt.imshow(\n",
+    "    np.flipud(img)\n",
+    ")  # in FITS, the lines of pixels are flipped, so we have to mimic this"
+   ]
   }
  ],
  "metadata": {