Problem in Image "Attachments" in Listing Manager

Hi,

I have two questions regarding images uploaded via “attachments” in Listing manager. They upload and display fine on listing page but when I return to edit listing and try to remove any of them. There is simply nothing to edit, all it shows the same browse option as there is nothing uploaded already. (image 1)

Secondly, I am unable to understand the pattern of the images shown in the actual listing page. I want to know which images will be by default for all user, currently its kinda random while i want my chosen mage to be displayed when page loads for the first time for user. Please note that i am not talking about featured image as its something else. (image 2)

Help appreciated!