UI button without image

hello everyone, I hope you can help me, I would like to change the image of the buttons when the mouse passes over the writing, without using an image as source, that is, leave only the writing then when the mouse passes over the writing activate the image, I tried through Inspector, but I didn't solve anything with alpha 0 working with "EventTrigger and then point enter", is there a solution? sorry if I can't speak well, I'm Italian