If pyvips (and libvips on sysstem) are installed, PyVIPS is used to extract width and height for images.
Compared to Wand, PyVIPS has the benefit of not loading the entire image in memory to extract width/height metadata for the image (works for multi-layer images also, such as TIFFs and PDFs). See this gist for a small memory analysis.
pyvips(andlibvipson sysstem) are installed, PyVIPS is used to extract width and height for images.