Preview displaying file size feature is missing

I like to use Preview to convert images between different types. The great feature I use the most is to preview the file size before converting.

For example, I open one png file and press cmd+shift+s to save it as another file. This will open a dialog with types I can choose. The dialog displays the original file size and it will update the file size corresponding to the type I want to save. This gives me a hint or PREVIEW for various types. I use this feature to save me great in terms of file size.

Now with the new PreView in Lion, no more save as feature. That's fine since version feauter is introducted. I found that Export would be an alternative. However, it does not provide file size as PREVIEW. That's a big lost for me. I just feel hadicated. I really don't want to save file first for comparing file size difference or use other tools(not sure if I can find any). I really want to get PREVIEW file size feature back! Is there anyway I can get the previous version of Preview back?

By the way, there is no shortcut key for Export.

David Chu