Hi! for it to work, you need to export it with DDS. I’m not sure what the right settings is in photoshop, but if you have GIMP, export it as DDS and select Compression as None.
in S4S, it tells you what kind of format you need to export the image as, because if you don’t import your image with the right kind of format, it shows the llama icon instead. I believe this happens the most to UI-related textures, so for non-UI mods like CCs, I don’t think it matters much (except for normal maps / specular maps / maybe swatch icons?)
some examples regarding the image format:
^ for the logo, it displays as RGBA8, which is DDS with no compression (other compression examples being DXT1 / DXT5)
^ image required must be exported as DXT1 without mip maps. If I were to import with png, it just won’t show up.
^ left is the original file format, which is DXT5. The right, which I imported with a png, shows a DXT5 with mip maps enabled. Sometimes importing w/ png works, sometimes not. If importing with a png shows the llama texture, then you can refer to the original texture to see what you should export your image as.
hope it helps!