Openning a png file in ubuntu, I can see the menu item for 'print to file'. How can I do the same on shell? PS: I prefer installing no extra package, due to lack of root access.
EDIT: the operating system is ubuntu 11.10
convert xyz.png xyz.pdf should do the trick.
man convert for more options.
If you want to convert multiple images, e.g. png files, into one single pdf use convert with the specified pdf filename at the end
convert *.png mydoc.pdf
It will merge all png files into a sinlge mydoc.pdf file in a descendant order.