Change Slider image

Hello all,

On my page (https://hylaumc.com/) i am attempting to change the slider image that is titled “support hispanic leadership” to another one. I clicked on the customize button and it took customizing menu but when I change the image after going to widget>Image slider> it wont work.

Maybe Im doing it wrong but it looks pretty simple.. I do save and publish and then refresh the page or open another page for the website to see if anything has changed but nothing..
Please help