Can I insert matplotlib graphs into Excel programmatically?

Openpyxl actually does support image embedding, and might work better for those using .png or existing .xlsx files! The code below appends an image to cell A1 of input.xlsx and saves the file as output.xlsx.

import matplotlib.pyplot as plt
import openpyxl

# Your plot generation code here...
plt.savefig("myplot.png", dpi = 150)

wb = openpyxl.load_workbook('input.xlsx')
ws = wb.active

img = openpyxl.drawing.Image('myplot.png')
img.anchor(ws.cell('A1'))

ws.add_image(img)
wb.save('output.xlsx')

EDIT June 2020: I've been informed openpyxl has changed since time of writing. Line 7 should be:

img = openpyxl.drawing.image.Image('myplot.png')

There is an extra .image in there now.

This worked out for me:

import openpyxl

wb = openpyxl.load_workbook('input.xlsx')
ws = wb.active

img = openpyxl.drawing.image.Image('myplot.png')
ws.add_image(ws.cell('A1'))

ws.save('output.xlsx')

Here is what I found from two different links on the web, that worked perfectly for me. Matplotlib allows saving png files which is what I make use of here:

from PIL import Image

file_in = "image.png"
img = Image.open(file_in)
file_out = 'test1.bmp'
print len(img.split()) # test
if len(img.split()) == 4:
    # prevent IOError: cannot write mode RGBA as BMP
    r, g, b, a = img.split()
    img = Image.merge("RGB", (r, g, b))
    img.save(file_out)
else:
    img.save(file_out)

from xlwt import Workbook
w = Workbook()
ws = w.add_sheet('Image')
ws.insert_bitmap(file_out, 0, 0)
w.save('images.xls')

The image part of the code is from Ene Urans response here http://www.daniweb.com/software-development/python/threads/253957/converting-an-image-file-png-to-a-bitmap-file.

The xlwt is simply form the documentation of xlwt I found at http://www.simplistix.co.uk/presentations/python-excel.pdf.