Add figure captions

docs/source/experiment.rst

@@ -392,6 +392,8 @@ the first few rings.
    :align: center
    :width: 80%
 
+   *Points generated for the innermost ring after selecting four points*
+
 After clicking on "Select Points", click somewhere on the innermost
 ring. This triggers the PyFAI Massif module, which automatically detects
 other points on the Debye-Scherrer ring that are contiguous to the
@@ -411,9 +413,10 @@ generate, using the ring pull-down menu.
    :align: center
    :width: 80%
 
-In this example, the pull-down menu was set to "Ring6". When enough
-rings have been defined, click "Calibrate" again to produce a more
-accurate refinement.
+   *Autogenerated rings after selecting "Ring6" on the pull-down menu*
+
+When enough rings have been defined, click "Calibrate" again to produce
+a more accurate refinement.
 
 The "Plot Cake" button can be used to generate a "cake" plot, in which
 all the powder rings, which are plotted against polar angle, should fall on vertical lines.
@@ -422,12 +425,15 @@ all the powder rings, which are plotted against polar angle, should fall on vert
    :align: center
    :width: 80%
 
+   *Cake Plot*
+
 This can be used to determine whether the calibration is sufficiently
 good over the entire angular range of the detector. If there is evidence
 of distortions at higher polar angle, it may be necessary to
 autogenerate more rings before an additional calibration.
 
 When the calibration is satisfactory, click "Save" to save both the
-powder calibration data and parameters to the configuration file. This
-process should be repeated for each entry, after which the dialog can be
-closed.
+powder calibration data and parameters to the configuration file. The
+calibration parameters can also be saved to a PONI file, using the
+"Export Calibration" button. This process should be repeated for each
+entry, after which the dialog can be closed.