Hello,
is there any way to set the sytle how the gift should be displayed, like with a background. Because my gifts are app transparent

I'm sharing my idea late but better late than never :) We don't have transparent gifs so I don't know if this could help. Maybe in CSS (fgift.css) you can add background colour:

.ow_avatar_console .fgift-gift {
    top: 0px;
    left: 0px;
    background-color: #ffffff;
}