extrJPG scans one or more input files for embedded JPEG files and extracts all found images to the disk. Such embedded images are very often, for example, contained in PDF files. Please note that extrJPG is still in an early stage and might, in some rare cases, dump non-JPEG files as well.

Download it from here:
extrJPG v0.1 (BSD)

Large file support (LFS) for files larger than 4GB is disabled by default but can be enabled by defining “LFS” in the source code. You may freely use extrJPG and the included source code under the terms of the BSD. It is also included in my JPEG Open Source Developers Package.