It is clearly a bug in the driver for package graphicx:
pdftex.def: ok.
dvips.def: ok for PostScript images, but clipping is not supported for bitmap images.
xetex.def: Clipping is not supported at all.
dvipdfm.def: The image is not trimmed, but distorted in the final area.
dvipdfmx.def: The whole image is put in the final area without distortion, but
empty space is put above the small image.
A remark to keepaspectratio: It has a meaning only if both the width and
height are specified. Thus the setting and values of keepaspectratio does not matter here.
There is a solution for dvips.def, dvipdfm.def and dvipdfmx.def if pdfTeX is used as TeX compiler (for DVI mode). Package bmpsize fixes as side effect the
defective drivers. And the package improves the bitmap inclusion making separate bounding box files obsolete. The driver xetex.def cannot be fixed this way, because XeTeX misses
primitives from pdfTeX (especially \pdffiledump), needed by bmpsize.
\usepackage[dvipdfm]{graphicx}
\usepackage{bmpsize}
keepaspectratioto false? – Ulrike Fischer Aug 21 '12 at 18:28keepaspectratiois not needed here and should not be used. Also note that thepxunit is apdftexextension and uses a fixed (but configurable) density which might not be correct for this particular JPG. Sometimes the images metadata are not fully correct, leading to a wrong display with LaTeX. – Martin Scharrer Aug 21 '12 at 18:50keepaspectratiokey has no effect. – bobobobo Aug 21 '12 at 19:46