Matplotlib is a popular Python library to create plots, charts, and graphs of different types. show() is used to plot a plot, but it doesn't save the plot to a file. In this article, we will see various methods through which a Matplotlib plot can be saved as an image file.

Methods to Save a Plot in Matplotlib

There are several ways to save plots inMatplotlib:

1. Usingsavefig()
2. Usingmatplotlib.pyplot.imsave()
3. Using the Pillow Library

1. Usingsavefig() Method

savefig() method is the most popular way of saving plots of Matplotlib. This function enables you to save a plot in the form of a file on your local system in different formats like PNG, JPEG, SVG, etc.

In this example, we are creating our own data list, and using Matplotlib we are plotting a bar graph and saving it to the same directory. To save generated graphs in a file on a storage disk, savefig() method is used.

importmatplotlib.pyplotaspltyear=['2010','2002','2004','2006','2008']production=[25,15,35,30,10]# Plotting bar chartplt.bar(year,production)# Saving the plot as a JPEG fileplt.savefig("output.jpg")# Saving the plot with additional parameters (this is optional)plt.savefig("output1.jpg",facecolor='yellow',bbox_inches="tight",pad_inches=0.3,transparent=True)

Output

2. Usingmatplotlib.pyplot.imsave()

imsave() function is another method to save a plot as an image file. It’s commonly used to save 2D arrays as image files, making it especially useful for working with image data.

importmatplotlib.pyplotaspltimportnumpyasnp# Generate random image dataimg=np.random.rand(100,100)# Save imageplt.imsave('sample_image.png',img,cmap='gray')

Output

3. Using the Pillow Library (PIL)

In certain instances, it could be helpful to transform a Matplotlib plot into aPillow (PIL) Image object and save it. This is specifically useful when one is dealing with image processing operations that need Pillow.

• BytesIO: We use aBytesIO buffer to store the plot image in memory, which can then be processed by PIL.
• fig.savefig(): Instead of converting the canvas directly to a string, we save the plot to the buffer in PNG format.
• Image.open(): We load the image from the buffer into a PIL image object.

importmatplotlib.pyplotaspltfromPILimportImageimportiofig,ax=plt.subplots()ax.plot([1,2,3],[1,2,3])# Save the plot to a BytesIO objectbuf=io.BytesIO()fig.savefig(buf,format='png')# Convert the BytesIO object to a PIL Imagebuf.seek(0)img=Image.open(buf)# Save the imageimg.save('pil_image_save.png')

Output