Help with saving custom armor texture as armor type of texture

I am trying to make a set of armor, (I want it to look better so I am not using default shape). So I imported the diamond armor texture (both layer_1 and layer_2), colored them, but when I tried to save them as a new texture, I couldn't save them as an armor texture, just block, item, or other. I saved them as "other" as that was the closest to armor. They didn't go into the armor texture category and instead into the mob texture category. As they are not in the armor texture category, I cannot use them as the texture of the armor I am making. Can someone tell me how to save them as an armor texture, or how I could use them as an armor texture for my armor element?