added image example

grum/exampledata.py

@@ -1,6 +1,6 @@
 import numpy as np
 
-from .descs import PlotDescription
+from .descs import PlotDescription, ImageDescription
 
 
 X = np.arange(100) / 10
@@ -31,4 +31,18 @@ for name, (xs, ys) in exampledata_raw.items():
     )
 
 
+name = "image"
+xdim = ydim = 100
+size = xdim * ydim
+shape = (xdim, ydim)
+
+img = np.arange(size).reshape(shape) / size
+img += np.random.random(shape) / 10
+
+exampledata[name] = ImageDescription(
+    name,
+    image=img
+)
+
+