Microsoft Office Files
Microsoft Office files -- Word, Excel and PowerPoint -- can all contain embedded images, and File Juicer can extract them without you needing to open the document.
Modern formats (DOCX, XLSX, PPTX)
Since Office 2007, the default formats are DOCX, XLSX and PPTX. These are ZIP archives containing the document content alongside all embedded images as separate files. File Juicer extracts those images directly. This is the quickest way to get all images out of a document at once without opening Office.
Older binary formats (DOC, XLS, PPT, PPS)
The older binary formats from Office 2003 and earlier store images differently but File Juicer can extract from these too. PPS (PowerPoint Slide Show) files are the same as PPT but open directly in presentation mode.
Vector graphics (WMF and EMF)
Windows Metafile (WMF) and Enhanced Metafile (EMF) are vector graphics formats commonly embedded in Office documents. File Juicer can extract them. You can open them in GraphicConverter or other tools.
Opening Office files without Microsoft Office
Office documents can also be opened with LibreOffice (free), which handles DOCX, XLSX and PPTX well, and with Apple's Pages, Numbers and Keynote. PowerPoint files can also be edited with Apple Keynote.