app.py

import gradio as gr
import numpy as np

counter = -1
COLORS = [(255, 0, 0), (0, 255, 0), (0, 0, 255)]


def fn():
    global counter
    counter = (counter + 1) % 3
    return np.full((300, 300, 3), COLORS[counter], dtype=np.uint8)


with gr.Blocks() as demo:
    btn = gr.Button()
    out = gr.Image()
    gr.DeepLinkButton()
    btn.click(fn=fn, outputs=out)
demo.launch()