How do I use graphics export options?

[serverdevil]

I'm converting a pdf to png (need the first page only) using the following command

unoconv -d graphics -o output/doc.png -f png -v doc.pdf

I need to restrict the image size to generate a thumbnail, for which I'd expect the export option to work as follows but it doesn't effect any change

unoconv -d graphics -o output/doc.png -e Width=25 -f png -v doc.pdf

Also, how do I combine multiple export filter options?

[regebro]

You can have multiple -e parameters, like -e Width=25 -e Height=100, but you are right, Width and Height does not work for me either. Neither does options of paper size work, so I think something has changed in the Uno API recently that means none of these options work anymore.

In any case, Libreoffice is not the best tool for this. I think I used ImageMagick last time I needed to make a PDF thumbnail. I think Ghostscript might work as well.

[serverdevil]

Thanks @regebro. Imagemagick is exactly what I ended up using.

[regebro]

OK, and it turns out that height and width works, but you have to specify both.