If you want to remove this image

then add this custom CSS code to your site's CSS code:
table#ecwid_loading_indicator td img {
display:none !important;
}
In the most cases when you alter any Ecwid element, you should add CSS code to your Ecwid CSS theme. In this particular case the CSS code should be applied as soon as Ecwid starts to load, so you have to add it to your site's CSS.