Basically, liferay shows image logo from ThemeDisplay object.
I tried looking at ServicePreAction.java
where themeDisplay
object gets prepared, I found below things that would be helpful to you.
Using code below you can get logourl
for any Site's Public or Private pages which you can set to html image tag.
LayoutSet siblingLayoutSet = LayoutSetLocalServiceUtil.getLayoutSet(
groupId, isPrivatePages);
if (siblingLayoutSet.isLogo()) {
logoId = siblingLayoutSet.getLogoId();
}
StringBundler sb = new StringBundler(5);
String imagePath=PortalUtil.getPathImage();
sb.append(imagePath);
sb.append("/layout_set_logo?img_id=");
sb.append(logoId);
sb.append("&t=");
sb.append(WebServerServletTokenUtil.getToken(logoId));
layoutSetLogo = sb.toString();