DOC: Add more details of using Scripts in the library

docs/getting_started.md

@@ -23,7 +23,7 @@ The example above creates an `asldata.ASLData` object, called `data`, which will
 !!! tip
     There are many other image file formatts that is accepted in the `asltk` tool. We adopted the `SimpleITK` API, then one can check the image formatts in the [official documentation](https://simpleitk.readthedocs.io/en/master/IO.html)
 
-# Example operation using `asltk`
+## Example operation using `asltk`
 
 The following examples can represents some situations on ASL data processing:
 
@@ -44,7 +44,7 @@ from asltk.asldata import ASLData
 ```
 
 
-# Load and process an image
+## Load and process an image
 
 As as standard notation, the `asltk` library assumes that all the image data files are storaged and manipulated using `numpy` objects. Therefore, the following code snippets can represents the `load_image` and `save_image` pattern adopted in the tool:
 
@@ -58,6 +58,14 @@ type(img)
 < numpy.ndarray >
 ```
 
+!!! warning
+    The `asltk` uses the `SimpleITK` library to load and save images due to it's long list of image format options, e.g. NifTI, Nrrd, MHA, etc. However, in order to transpose to `numpy.array` data format for image processing, it is important to note that the image space rasteting format relies as follows:
+    ```
+    SimpleITK -> (x,y,z,...,n_d)
+    Numpy -> (n_d, ..., z,y,x)
+    ```
+    Where the `n_d` represents a higher order dimension in the data.
+
 2.  Saving and image
 
 ```python
@@ -72,3 +80,16 @@ Basically, one can use out tool for the general pipeline:
 * Loading a data and metadata, 
 * Choosing the right ASL processing algorithm for the data loaded
 * Saving the outcomes generated in the `asltk` tool.
+
+## Using the library scripts
+
+Another quick and easy way to learn how to use the ASL processing algorithms implemented in the `asltk` library is using our Python scripts.
+
+All the scripts are located in the `asltk/scripts` folder, which is basically a simple way to run a determined kind of ASL processing.
+
+At the moment, there are the following scripts avaliable:
+
+1. `cbf.py`: Python script focused on calculating CBF/ATT maps using pCASL images. This script is based on the `CBFMapping` class.
+2. `te_asl.py`: Python script focused on calculating T1 relaxation exchange time between Blood and Grey-Matter (T1blGM) map using pCASL multi-TE ASL images. This script is based on the `MultiTE_ASLMapping` class.
+
+Additional scripts can be added in the `asltk` library, by the community contribution. If it is your interest, then go to the [developing scripts](contribute.md) section at the developer guidelines.