image with hotspots transparent tooltip with image

Hi,
I am using a image with hotspot on one of my pages and I already got the pulse transparent, but when I´m adding a image into the image with hotspots, the tooltip gets displayed with white background, although i am using a logo image without a background.
How can I achieve a transparent background for the tooltip image?

.av-hotspot-container .av-image-hotspot_inner {background: transparent !important;}

I am already using this css snipet but i think it only works when text is displayed?

Regards
Michael