header widget image has disappeared

Hello,

I set up an image within a header widget when I built the site which was working perfectly but I have just noticed that it has disappeared!
This is the code that my developer gave me which worked perfectly well before
/* Anna changes for advert image in header */
#header .widget {
position: absolute;
right: 80px;
top: 5px;
max-width: 300px;
height:78px;
padding: 0;
}
@media (min-width: 991px) {
.html_header_top.html_header_sticky.html_large.html_main_nav_header .av_minimal_header .main_menu ul:first-child > li a {
height: 30px;
line-height: 30px;
}
#top nav .social_bookmarks {
top: 0;
margin-top: 0;
}
.main_menu{
margin-top: 80px;
}
}

@media (max-width: 990px) {
#header .widget {
right: 220px;
max-width: 200px;
height: 90px;
margin: 0 auto;
}
#header .widget img{
vertical-align: middle;
}
}

@media (max-width: 766px) {
#header .widget {
position: relative;
text-align: center;
right: unset;
height: auto;
}
}
#header .widget:before, #header .widget:after {
display: none;
}

I checked and the image is still situated within the widget – it just no longer appears.

Could you help please?

Logins provided
Many thanks
Kim