Hello Zona. I did reply in May to your previous question. There is a lot of information on this particular forum about CELTA and requirements. As you are doing the course in the UK, it is possible that your centre will use the new New Headway series. You could start by visiting a decent bookshop and having a look at the topics covered in that series. As for pictures you might consider collecting illustrations of food, customs, fashion, famous landmarks - for starters.

Michael Swan has written many books. It you mean Practical English Usage, then this is more of a reference source than something you would read all the way through. A number of students on the course I did had some problems with the language analysis. For this section of the course I would suggest you look at How English Works: a grammar practice book. by Michael Swan and Catherine Walter Oxford University Press (reprinted 2009).