[texhax] includegraphics and image scaling

[Heiko Oberdiek]

On Thu, Dec 09, 2010 at 05:12:07PM -0500, Peter Davis wrote:

> On Thu, Dec 9, 2010 at 4:51 PM, Martin Schröder <martin at oneiros.de> wrote:
> 
> > 2010/12/9 Peter Davis <pfd at pfdstudio.com>:
> > > I have a couple of .jpg files that are 1024 x 768 pixels, with a
> > resolution
> > > of 96dpi.  If I just include them in my LaTeX document with:
> > > \includegraphics{xyz.jpg}
> > > they appear on the page at 1024bp x 768bp.  In effect, the resolution is
> > > ignored, and they're scaled up by 1/3.

> > What's the output of
> > - "identify -verbose" (from imagemagick)

> Image: Chrysanthemum.jpg
>   Geometry: 1024x768+0+0
>   Resolution: 72x72
>   Print size: 14.2222x10.6667
>   Units: PixelsPerInch

The resolution is 72dpi, not 96dpi.

width = (1024 dots / 72 (dots/in)) = 14.2222 in
Unit conversion: 1in = 72bp
==> width = 1024bp

Therefore the image is shown in the correct size on the paper.
The graphicx package allows you to scale the image,
see options `scale' or `width'.
Documentation of LaTeX's graphics bundle in file `grfguide.pdf'.

Yours sincerely
  Heiko Oberdiek