add debugging on pngdec

inky-lovelace.py

@@ -35,14 +35,23 @@ global graphics
 def display_image(j):
     # Open the PNG file
     j.open_file(CONFIG.FILENAME)
+    graphics.set_pen(0)
+    graphics.set_font('sans')
+
     # Decode the PNG
-    j.decode()
+    try:
+        j.decode()
+    except Exception as e:
+        # if that fails, try to recover enough to show
+        # an error. This seems to fail sometimes and I
+        # don't know why.
+        del j
+        gc.collect()
+        graphics.text( e, 10, 200, scale=1 )
 
     # write the date/time at the top
     tz_seconds = (CONFIG.TZ_OFFSET * 3600)
     year, month, day, hour, minute, second, dow, _ = time.gmtime(time.time() + tz_seconds)
-    graphics.set_pen(0)
-    graphics.set_font('sans')
     # display.text(text, x, y, wordwrap, scale, angle, spacing)
     graphics.text(f"{hour:02}:{minute:02} {year}-{month}-{day}", 230, 10, scale=0.5)
     gc.collect()