I am trying to resize the pencil svg on https://jam-icons.com. It is 32 x 24 pixels, and I want it 32 x 32 pixels, but still square in aspect ratio. I have it, as I have achieved this before, but I want it in a different colour. I'm not sure/forgot what to set on the dimension parameters to re-achieve this sizing, and keep the border a uniform size.

For example see attached

I get the icon canvas size to be 24x24 pixels ? 

This is how I would do it.

Enable snap to page in the vertical snapping toolbar to the right of the Inkscape window.

Draw a rectangle from top left > bottom right snapping to the page corners. 

Change to the selection tool

Select all, then group.

Lock the width and height in the selection toolbar then type in the pixel width you want - so 34.

Select all if not selected then - Edit>Resize page to canvas

Ungroup, delete the rectangle.

Then export ( with page selected in the png export panel ) 

There might be a simpler way of course :)

In Jam Icons there is a setting at the top right for the 32 pixel version

Where can I type in the width that I want, from your instructions

Thanks