from PIL import Image

img = Image.open(r'c:\Projects\JX\logs\game_53668.png')
# Crop client area: (3, 26, 803, 626)
client_img = img.crop((3, 26, 803, 626))
client_img.save(r'c:\Projects\JX\logs\client_800x600.png')
print("Saved client_800x600.png with size:", client_img.size)

# Search for the button border or text
# The button 'Bắt đầu trò chơi' has a distinct metallic frame around y=370..420
pixels = client_img.load()
w, h = client_img.size

# Let's inspect rows around y=380..420 at x=400
for y in range(370, 430, 5):
    r, g, b = pixels[400, y][:3]
    print(f"y={y}: ({r}, {g}, {b})")