When "Save as image" in File Menu in the Menu Bar is selected, the currently displayed page or the indicated region (Display->Region) is saved to a file in BMP or EMF or BMC format.
For another format, the corresponding batch file in the directory utility is serched and if it exists, it is executed. For PDF the batch file utility\dvi$pdf.bat (in general utility\dvi$extension.bat) is executed.
dvipdfmx newer than 20040204 is necessary for PDF format.
Then the following parameters can be used in general.
%1 horizontal offset (by cm). default 2.54cm
%2 vertical offset (by cm). default 2.54cm
%3 width
%4 height
%5 page number
%6 the full pathname of the DVI file
%7 the full pathname of the output
%8 horizontal offset (by cm). default 0cm
%9 vertical offset (by cm). default 0cm
Other formats without the corresponding batch file are also possible if the corresponding ABC output plugin is installed in the directory of dviout or the directory of Susie plug-in or its subdirectry named exp_plug. For example, expng.xpi is for PNG format. The format is decided by the extension of the filename to be indicated.
In the case of BMP or EMF format, it can be copied to Clipboard in place of saving it to a file.
If BMP or BMC format etc. is selected, the saved page is in gray scale when antialiasing is in effect, and colors as in HyperTeX documents or after string search.
However, color images which has more than black and white are not properly handled, nor colored or reversed (in black/white) characters generated by LaTeX2e graphics package.
On the other hand, if EMF(Enhanced Windows MetaFile) format is selected, color images can be handled and TrueType fonts are recorded as scalable fonts. Hence this format is more efficient in enlarging or/and shrinking size.