Can I tell
graphicx somehow which graphic format to choose when I omit the file extension in
includegraphics and both a PDF and a PNG version of the same image exist? The reason is that I have some very large PDF vector graphics (in terms of file size/drawing primitives) that take a pretty long time to load each time I view the document. I would like to convert them to PNGs while working on the document and only use the PDF versions in the final document. Therefore, a global option that I can switch in the end would be great.
An additional plus would be to do the conversion to PNG on the fly during the LaTeX run if there is a PDF that has not been converted to PNG yet, if a tool for that exists. (I know how to use
convert, but not how to include it automatically in LaTeX.)