how to access image based on date

We developing on web_site.We have one 4 images.Images names like this

16-04-2015
15-04-2015
14-04-2015_1
14-04-2015_2
13-04-2015
12-04-2015
11-04-2015

images we placed one folder in my project.First load current date image.We have two buttons next and previous buttons.We need is if we click next button next Date image will be come.if we click on previous button we need previous data image will come

Please help me