I'm writing up some mathematics notes in LaTeX using Texmaker, and want to include some diagrams (from image files).
When I include the graphicx package, I keep getting a pop-up entitled 'Package Installation', saying that 'tex\context\base\supp-pdf.mkii' is missing, and asking me to install mptopdf, whenever I compile the file to pdf.
If I click install, the pdf compiles and loads fine (at least it seems to), but it prompts me again to install the next time as well!
I could just uncheck the box about 'show this dialog', but I feel it might be better to address the issue properly. Any suggestions?

Here's my preamble:
\documentclass[a4paper,12pt]{article}
\usepackage{amsthm}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage[top=1in, bottom=1in, left=1in, right=1in]{geometry}
\usepackage{graphicx}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{definition}{Definition}
One line where I want an image is
\includegraphics[width=10cm]{trianglesymettries.png}
But I get the pop-up even without this line. (It only stops if I remove '\usepackage{graphicx}'.)
I'm editing using Texmaker 4.0.4, with the MiKTeX 2.9 distribution on Windows 8.