As mentioned in Section 3.5, LaTeXML generally requires image files of type .png, .jpg, .pdf or .eps (encapsulated PostScript), while latex requires image files of type .eps. The Makefiles provide default commands to automatically create .eps files on demand from .png, .jpg, or .pdf files, using the ImageMagick convert program.
A number of document illustrations are produced using the Interviews IDraw graphics application, and stored as .idr files. A default Makefile command automatically converts these to .eps (by a simple copy operation since .idr files are themselves encapsulated PostScript).
In addition to raw image files, the Linux program Xfig is used to create both diagrams and annotated images that are marked up with explanatory text and graphics. Files produced by xfig use the extension .fig, and are also stored in the images directory as image “source” files. External images can be imported into Xfig; these are not stored in the .fig file but are stored externally in their original image file.
Be careful about deleting image files that do not appear to be referenced in the documentation: they may in fact be referred to by a .fig file. To determine the image file associated with an imported Xfig image, select the "Edit" tool within Xfig and click on the image object. This will create a properties panel that displays the file.