if you take the ...multi\checkboxes demo and add a button to the form then add this code to the buttons click event, the checked thumbnails are not deleted.  Why?  After checking 3 thumbnails, one thumbnail remains checked and is not deleted.
// Delete checked images
procedure TMainForm.DeleteChecked1Click(Sender: TObject);
var
  I: Integer;
begin
  for I := 0 to ImageEnMView1.ImageCount-1 do
    if ImageEnMView1.Checked[I] then
    begin
      ImageEnMView1.DeleteImage(I);
    end;
  ImageEnMView1.Update;
end;
Bill Miller
Adirondack Software & Graphics
Email: w2m@hughes.net
EBook: http://www.imageen.com/ebook/
Custom Commercial ImageEn Development