title: Save images with high resolution with matplotlib
body: <p>i'm generating a dataset from 1D signals with a 2D transformation that generates 2D pictures. I'm using matplotlib to save the output with the following line:</p>
  <pre><code>plt.savefig(name_s , dpi = 'figure' , bbox_inches='tight', pad_inches=0.0 , format='png')
  </code></pre>
  <p>I'm having some trouble unerstanding if an high numerical dpi value is needed or if it is just a rescale, in particular when with the dpi = 'figure' parameter the function outputs a lower resolution image.</p>
  <p>Moreover, if there is a specific format i can use to generate or save better images or any advice in general is gladly accepted.</p>