Per 'drag 'n' drop', it's how I prefer to do things. Setting up an 'external library' is much more convoluted than I'd like, and far from intuitive. Also, with half-a-Terabyte of CAD & Poser-related 'stuff' ranging from P3 to this afternoon, I'd never keep the laden library straight. Instead, I've an 'E:' drive with a bunch of folder trees, each group or category with lots of folders, each with my 350x350 folder.jpg, the original zip, some promo pics, a nik-note if necessary and the essential runtime. This may hold just one download, or a sprawling product set of props, poses and textures...

One 'gotcha': If you 'DnD' into your workspace, Poser may not find the associated textures etc, so prompts for them. Yet, many years along from when this first bugged me in P4, it still often hides the first few characters of each sought file's name off the left of input field. Must left-arrow to show. So very, very silly...

And, yes, I've reported this quirk in the official wish-list thread.

FWIW, this PC runs 3½ displays, the last being 'Ye Olde DeskToppe PC' screen via a KVM. Being a 'trad' 1280x1024, it is a handy shape for the Poser manual...