I don’t think that I need to explain, just how to do it, but without using any addons?
edit: not sure if it’s just me, but it appears that I sent 2 pics of the same thing, but in the edit section I only see one, so I can’t remove it.
Hi 
Use ad - Images as plane…Pick Your picture…Pam.!!! all is setup for You…
Look left in the Browser for other settings…When You load it.
Then go Node Editor To see how it’s done…And tweak it if You need…Puff Puff
Tai
Forgot to say…Be sure to use a .Png or other there can show transparent.
I must add, although it is an addon, it already comes installed with Blender, so all you need to do is enable it in the settings.
I’ll try it out, but is there a way to do this using just regular material settings? There are several alpha related things in the materials section, but I have no idea what they mean.
use images as planes yes but you need to makesure the use alpha check box is checked on the import page or it wont include the alpha channel in the import
There is a tutorial out there showing how to do trees effectively using this method. It doesn’t use just simple images though, you need to build some basic grass clumps, (only a few), then bake both the image for mapping and normal maps. It’s very effective, I’d recommend giving it a shot.
Part1:
Part2:
Screenshot vs render.
The black edges on the trees can be dialled back by reducing the strength of the normal map intesity.
Attachments
Take the alpha output from you image, and connect it to the Factor input of a Mix shader. Connect a Transparent Shader to the top input of the Mix Shader, and your Diffuse or Principled or whatever shader into the bottom input of the Mix.