if custom_index do this

i'm trying to look for something related to copy the logic. been cracking my brains out.

what i want is to place an image at the elgg_topbar, but i want it to only appear on all pages except for custom_index.

anyone has any ideas how to do this? i hv to find something related to this.. but i can't think of any.

if current page = custom_index > do this. so how can i detect the current page?