Easy Reference is a Blender add-on that brings reference images into your scene and scales them to fit. You point it to the folder where your images are stored, select the ones you need, and they appear listed in the panel. Assigning positions is done by picking from six views: FRONT, BACK, LEFT, RIGHT, TOP, and BOTTOM. Pressing the 'add as reference images' button places each image on its view, and every image takes the prefix of the view you chose.
Clicking a view name in the panel switches to that view and selects the image, so you skip the usual 1, Ctrl+1, 3 and Ctrl+3 shortcuts. A slider moves the images apart, and the Model Box helps with positioning and scaling. You enter the length, height, and width of your model, then lock the box, position your references, and lock them before modelling.
For a single blueprint holding all views, the 'copy Image' button duplicates it as needed. The 2-point scale tool scales one image from a known dimension, and 'copy scale to all' matches the rest. Architectural work also has a scale line tool, usable in FRONT or TOP view.