GUIStyle textures pixelated, but appears smooth for GUISkin

For some reason, why I use the same smooth-looking texture for a GUISkin normal or hover, it looks smooth, but on GUIStyle (assigned via the same drag and drop in the Editor), it looks pixelated…

I am not sure what is happening here at all. Does GUIStyle textures require a different format, or some sort of stretch constraint?

On the same element ? If the element drawn with the skin’s style has the same ratio as the texture when the element drawn with the style doesn’t, or the other way around, I guess it could be that.