Some "Properties" in digikam sidebar are unknown or unavailable

Why can't I get Image Properties Dimensions or other items ?

Digikam uses KDE metainfo plugins to display the file properties. If the "Dimensions" value is "unknown", it means you don't have this plugin. On debian based distribution (eg Ubuntu), install kdegraphics-kfile-plugins package.

Note: even if you have the right plugin, some other properties (Bits depth, Sensitivity, Compression, ...) can still be unavailable depending on the image file (and your digital camera).