fix(label): Use buffer for image

.gitignore

@@ -1,7 +1,8 @@
 # Created by https://www.toptal.com/developers/gitignore/api/macos,python,visualstudiocode
 # Edit at https://www.toptal.com/developers/gitignore?templates=macos,python,visualstudiocode
 
-test.png # File generated by test server
+# File generated by test server
+test.png
 
 ### macOS ###
 # General

inventree_phomemo/phomemo_label.py

@@ -5,6 +5,7 @@ from django.core.validators import MaxValueValidator
 
 # printer supportt
 import socket
+import io
 
 # InvenTree plugin libs
 from plugin import InvenTreePlugin
@@ -56,14 +57,16 @@ class PhomemoLabelPlugin(LabelPrintingMixin, SettingsMixin, InvenTreePlugin):
         label_image = label_image.convert('L').point(fn, mode='1')
 
         ##### Convert to phomemo
+        img_byte_arr = io.BytesIO()
+        label_image.save(img_byte_arr, format='PNG')
+        img_byte_arr = img_byte_arr.getvalue()
 
         # Send the label to the printer
         try:
             print_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
             print_socket.settimeout(5)
             print_socket.connect((ip_address, port))
-            data = label_image.tobytes("PNG")
-            print_socket.send(data)
+            print_socket.send(img_byte_arr)
             print_socket.close()
         except Exception as error:
             raise ConnectionError('Error connecting to printer server: ' + str(error))