Dear convertix,
Please open file "CuteSoft_Client\Gallery\Popup\Default\Code.js", when you delete photo, it will call the following function:
menu.Add(1,GalleryLocalize.CLICK_DELETE,null,ToDelegate(this,function Delete(){
this.Confirm(FormatText(GalleryLocalize.CONFIRM_CLICK_DELETEPHOTO,photo.Title),function(res){
if(!res)return;
this.Browser.AsyncDeletePhoto({CategoryID:photo.CategoryID,PhotoID:photo.PhotoID});
},this);
}));
PhotoID will return the filename to be deleted.
Thank you for asking