[kapaka]

I am trying to get a taste for manga, so I have recieved one from a friend in .cbz format. This is a .zip file with many .jpg files, one for each page.
If I load it as a .zip file and open it, there is only one single picture, first page. To read the next page I have to get back, open the second and so on...
As you can see it is not a good way to read.
So to what format should I convert the .zip file? and with what converter?
What size should each page be to best reading? What resolution?
As the size of the original manga is only slightly bigger, should I keep the original size or should I resize it for reading?

Thanks for your help