title: How to print a logo on labels using a Zebra printer and sending ZPL instructions to it
body: <p>I would like send ZPL instructions to a Zebra printer (GK420t for now).
  I'm printing 50mm x 20mm labels.
  I would like a logo (small ~ 5mm x 5mm image) to be printed on the upper left corner of the label.</p>
  
  <p>I would like to know the steps I should follow to do this.</p>
  
  <p>I have been reading and trying a few things from the ZPL manual but I don't really understand how it works and couldn't find a working example.</p>
  
  <p>It looks like I have to "load" the image into the printer first (in a so-called "storage area"/DRAM?) and then print it.</p>
  
  <p>The <code>.GRF</code> file extension is mentioned many times in the manual.
  I couldn't find the tool to convert a .PNG or .BMP image into a .GRF file.
  I read that a .GRF file is an ASCII HEX representation of a graphic image... but it didn't help me do the work.</p>
  
  <p>I could print the logo on the labels using the "Zebra Setup Utilities", by "Downloading Fonts and Graphics", choosing any available .MMF file, adding a .BMP picture, downloading it [to the printer] and printing a test page.
  But until now, I couldn't do it using ZPL instructions.</p>
  
  <p>I am also wondering what are the best dimensions I should use given the fact that I need a small image ~5mm x 5mm to be printed on the labels.
  The image I printed is a 40px x 40px image.
  Also, if I have to make a .GRF file from an original image what should be the type of this file (.BMP, .PNG, .JPG)?</p>
  
  <p>Can you advise me how to proceed?</p>