Is it possible to have a pic of the file type of attachment?
 

Ok so I learned how to get a pic up.
Is there a way to change the size of it? So small.

You need to explain better what you want and perhaps provide and image so we can see what you have and what you want.

Sorry I was not too descriptive. Here's a pic
https://vborg.vbsupport.ru/external/2009/03/45.png

You see the zip icon is very small.
Also is there a way in permission to make it so that in order to view what attachment or images, there is a notice that they must register. For example:

https://vborg.vbsupport.ru/external/2009/03/46.png

If you want the zip icon to be larger, then you will have to create a larger one and replace it in your image files.

I have created a giant icon but it eventually gets resized

Try changing the size in the template - postbit_attachment.