Tip-torial: Adding a background/reference image in Blender
This is for blender 2.79, since that is what I (now) use for posing. Â Your âmileage may varyâ with other versions.
To add a background/reference image is super easy and helpful (to me at least). I donât know how I was living without it previously.  (Making due with side-by-side windows.)  Anyway, to add one, you need to be in Orthographic Mode (hit â5âČ on the keyboard until you get out of perspective mode.  Hint: see my picture above).  Next, if the properties panel isnât showing, hit the âNâ key to bring it up.  Scroll down to the bottom to âBackground Imageâ.  Tick the check box to turn it on.  Then click âAdd Imageâ. In my screenshot, it shows the filename of my image (the bottom green arrow), but yours will say âOpenâ, just click that and select your photo. Now, you can change the options. The image will likely be too large and centered down on the axis. Just poke around on the scale, rotate, X and Y properties to adjust where it shows up.
My âAxisâ property currently says âall viewsâ, so my picture will show up whether I look at it front, back, left or right. You can set yours to whatever you like. You can even add multiple images - one for each view. Go crazy!
ALTERNATELY, you can drag and drop an image onto the background if you like. Â And then go into properties and scale/move it as you like.
Bonus : If you arenât aware of it, 2 different people upgraded the CLIPtools to be usable with Blender 2.79 - @amuhavâ (here) and @younameitillposeitâ (here). Amuhavâs came out first (that and I follow her!), so that is the one Iâve been using. I canât vouch for the other version, but Iâm sure it is good too!
(NOTE: the pose in the image is IN PROGRESS, so donât be giving me crap for how janky it looks like right now. Thatâs like literally 5 minutes work...)