Can't size image down in mobile

Site URL: https://dushacastro.com/work

I have a rotating .png on my website. I want it to be smaller on mobile than on desktop

I can make it disappear but for some reason I can't make it smaller

When I try to change the size using (below) the size doesn't change.

 {width:120px} 

But when I try to hide it for mobile using (below) the image disappears from mobile

{display: none:} 

Here is my current code:

@media only screen and (max-width:770px)
{#block-yui_3_17_2_1_1657344033920_6712.sqs-block-image
{width:10px}}

Maybe try:

@media only screen and (max-width:770px) {
    #block-yui_3_17_2_1_1657344033920_6712 img {
        width:10px !important;
    }
}

Which image are you referring to?