I forgot to put the "side" in the image names. My bad. I've been coding 8 hours per day for the last 2 week, ugg.That won't work. The tag for side images has to be "side", so "side eileen.webp", "side eileen sad.webp" etc...
If you want to do different expressions and outfits, it's slightly more complicated, but still pretty simple in the grand scheme of things.
I actually put a little more effort into my side images at the beginning of my project, to save me time in the future. I have every characters side images stored in a single Photoshop file. I can select the character with emotion, the frame, and the background and then just export the new side image in seconds. I also have the corresponding DUF files created for each character so, when I want to make a new emotion or put on different clothes, different hair etc... I just load up that character's duf file and do the changes then render. The render is already pre-sized to fit perfectly in my photoshop file.
Took me a while to smooth this out, but now I can add new characters and generate their sides in minutes, instead of hours.