thumbnail: add example

artiq/examples/master/repository/thumbnail.py

@@ -0,0 +1,21 @@
+import io
+
+import numpy as np
+import matplotlib.pyplot as plt
+
+from artiq.experiment import *
+
+
+class Thumbnail(EnvExperiment):
+    def build(self):
+        pass
+
+    def run(self):
+        pass
+
+    def analyze(self):
+        plt.plot([1, 2, 0, 3, 4])
+        f = io.BytesIO()
+        plt.savefig(f, format="PNG")
+        f.seek(0)
+        self.set_dataset("thumbnail", np.void(f.read()))