For use with a HiDPI screen, I would like to increase toolbar and menu item icons in GTK+ 2, possibly to 48×48 px.
For the Gimp, I am able to increase tool icons by specifying in the theme's
GimpToolPalette::tool-icon-size = dialog
As far as I can tell, if there are no icons of the specified size available, smaller ones are scaled up. Great!
For all GTK+ 2 applications I tried increasing icon size by specifying in
gtk-toolbar-icon-size = GTK_ICON_SIZE_DIALOG
However, this has no effect, at least in the applications that I tested, for example Geeqie. Here the icons are still small.