Today I used dia -t -s

["Octavio Alvarez" <alvarezp alvarezp ods org>]

I was asked to deliver some diagrams Dia diagrams I did, in PNG format.

I just would imagine the nightmare it would have been to do this under  
"other" diagramming tools.

for D in *.dia; do dia -t png -s 1024x $D; done

I just checked them afterwards to do a second pass to save bigger diagrams  
in a different size.

Thanks for this option, Dia developers!