Place image over PDF

I combined ReportLab and pypdf to insert an image directly without having to generate the PDF up front:

from pyPdf import PdfFileWriter, PdfFileReader
from reportlab.pdfgen import canvas
from StringIO import StringIO


# Using ReportLab to insert image into PDF
imgTemp = StringIO()
imgDoc = canvas.Canvas(imgTemp)

# Draw image on Canvas and save PDF in buffer
imgPath = "path/to/img.png"
imgDoc.drawImage(imgPath, 399, 760, 160, 160)    ## at (399,760) with size 160x160
imgDoc.save()

# Use PyPDF to merge the image-PDF into the template
page = PdfFileReader(file("document.pdf","rb")).getPage(0)
overlay = PdfFileReader(StringIO(imgTemp.getvalue())).getPage(0)
page.mergePage(overlay)

#Save the result
output = PdfFileWriter()
output.addPage(page)
output.write(file("output.pdf","w"))

Its been 5 years, I think these answers need some TLC. Here is a complete solution.

The following is tested with Python 2.7

Install dependencies

pip install reportlab 
pip install pypdf2

Do the magic

from reportlab.pdfgen import canvas
from PyPDF2 import PdfFileWriter, PdfFileReader

# Create the watermark from an image
c = canvas.Canvas('watermark.pdf')

# Draw the image at x, y. I positioned the x,y to be where i like here
c.drawImage('test.png', 15, 720)

# Add some custom text for good measure
c.drawString(15, 720,"Hello World")
c.save()

# Get the watermark file you just created
watermark = PdfFileReader(open("watermark.pdf", "rb"))

# Get our files ready
output_file = PdfFileWriter()
input_file = PdfFileReader(open("test2.pdf", "rb"))

# Number of pages in input document
page_count = input_file.getNumPages()

# Go through all the input file pages to add a watermark to them
for page_number in range(page_count):
    print "Watermarking page {} of {}".format(page_number, page_count)
    # merge the watermark with the page
    input_page = input_file.getPage(page_number)
    input_page.mergePage(watermark.getPage(0))
    # add page from input file to output document
    output_file.addPage(input_page)
   
# finally, write "output" to document-output.pdf
with open("document-output.pdf", "wb") as outputStream:
    output_file.write(outputStream)

References:

pypdf project page:
https://pypi.org/project/pypdf/

Reportlab docs:
http://www.reportlab.com/apis/reportlab/2.4/pdfgen.html

Reportlab complete user guide:
https://www.reportlab.com/docs/reportlab-userguide.pdf

This is what worked for me

from PyPDF2 import PdfFileWriter, PdfFileReader

def watermarks(temp, watermar,new_file):
    template = PdfFileReader(open(temp, 'rb'))
    wpdf = PdfFileReader(open(watermar, 'rb'))
    watermark = wpdf.getPage(0)

    for i in xrange(template.getNumPages()):
        page = template.getPage(i)
        page.mergePage(watermark)
        output.addPage(page)

        with open(new_file, 'wb') as f:
            output.write(f)

Thx to the previous answers. My way with python3.4

# -*- coding: utf-8 -*-
from io import BytesIO
from PyPDF2 import PdfFileWriter, PdfFileReader
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4

def gen_pdf():
    # there are 66 slides (1.jpg, 2.jpg, 3.jpg...)
    path = 'slades/{0}.jpg'
    pdf = PdfFileWriter()

    for num in range(1, 67):  # for each slide
        # Using ReportLab Canvas to insert image into PDF
        imgTemp = BytesIO()
        imgDoc = canvas.Canvas(imgTemp, pagesize=A4)
        # Draw image on Canvas and save PDF in buffer
        imgDoc.drawImage(path.format(num), -25, -45)
        # x, y - start position
        # in my case -25, -45 needed
        imgDoc.save()
        # Use PyPDF to merge the image-PDF into the template
        pdf.addPage(PdfFileReader(BytesIO(imgTemp.getvalue())).getPage(0))

    pdf.write(open("output.pdf","wb"))


if __name__ == '__main__':
    gen_pdf()

This is quite easy to do with PyMuPDF without merging two PDFs:

import fitz

src_pdf_filename = 'source.pdf'
dst_pdf_filename = 'destination.pdf'
img_filename = 'barcode.jpg'

# http://pymupdf.readthedocs.io/en/latest/rect/
# Set position and size according to your needs
img_rect = fitz.Rect(100, 100, 120, 120)

document = fitz.open(src_pdf_filename)

# We'll put image on first page only but you could put it elsewhere
page = document[0]
page.insertImage(img_rect, filename=img_filename)

# See http://pymupdf.readthedocs.io/en/latest/document/#Document.save and
# http://pymupdf.readthedocs.io/en/latest/document/#Document.saveIncr for
# additional parameters, especially if you want to overwrite existing PDF
# instead of writing new PDF
document.save(dst_pdf_filename)

document.close()