I'm new and just listed my first 10 books. I did notice that some of the pictures of the covers of my books on the list do not look like my actual books cover.

Will this make a difference when someone requests this book? Is there a way to pick which front cover a particular book has? I don't know if I should remove those books that look different from the one I have from my list?

No, the cover does not have to match. A book can be re-issued several times with several different covers. 

The title, author, ISBN and book type (hard cover, paperback, etc.) need to match.

Ok great! Thank you for the reply.

Welcome to PBS Janet!  As Lisa posted, you merely need to match ISBN, title, author, and binding.  Cover changes are handled differently... If the member requesting your book(s) wants a specific cover, they need to set up an RC (Requestor Conditions) stating exactly what they want.  Otherwise, it is assumed that the requesting member does not care which cover is on your book, merely that it is the title requested and in postable condition.

Requestor Conditions (when used) arrive attached to the book requests, you can't miss them and have to accept or decline before you can accept the book request.  If the requestor has an RC and your book does not meet the requesters additional conditions (RC) you merely opt to decline and your book is offered to the next wisher.  If your book meets RC, you accept and mail as usual.