# Is it OK to scale image by changing its resolution?

Assume I have an image fruit240.jpg of 800 pixels by 600 pixels at resolution of 240 dpi.

Normally I can scale it by half using the following way.

\documentclass{article}

\usepackage{xcolor,graphicx}

\parindent=0pt
\fboxsep=0pt
\fboxrule=5pt

\begin{document}
{\color{red}\fbox{\includegraphics[scale=0.5]{fruit240}}}
\end{document}


Doubling resolution by invoking ImageMagick's convert as follows apparently makes the same effect as scaling by half.

convert fruit240.jpg -density 480 fruit480.jpg

\documentclass{article}

\usepackage{xcolor,graphicx}

\parindent=0pt
\fboxsep=0pt
\fboxrule=5pt

\begin{document}
{\color{red}\fbox{\includegraphics{fruit480}}}
\end{document}


Is it OK to scale image by changing its resolution?

-

Yes, changing the resolution using the -density operator in ImageMagick (or through the Information window in IrfanView) is a lossless operation. From the ImageMagick documentation: