# Import screenshot into LaTeX PDF blurry

I am taking notes as a PDF from my textbook with LaTeX, and I am taking a screenshot with Shutter of some pictures in the book and trying to include them in the notes, but the image keeps coming out blurry. From Googling I believe this is because the DPI is wrong, but I have been unable to fix this.

Here is the image I am trying to include:

but here is how it comes out in the PDF:

A minimum example:

\documentclass{article}
\usepackage{graphicx}

\begin{document}
\includegraphics{graph_types.png}
\end{document}


I am using Ubuntu 14.04.2, Shutter 0.93.1, and pdflatex 3.1415926-2.5-1.40.14

I believe that it is a smoothing effect. Observe that the blurred picture is slightly larger. If I zoom the webpage in Firefox (using CTRL-+), the smaller picture also becomes blurred.