Uploading photos perfect locally but changes not live

I have my site up and running about 6 months and upload through cyber duck. On the index page I have a slideshow of photographs that I change regularly through my CSS page. All working well until I changed the photos again and it looks perfect locally but when I load it through cyber duck the photos have not changed. Can anyone help please? This is my first we page. I just can't figure out what's going on? Thanks Rachel