Adding slides to active slider

Hi there, I am facing some issues with adding slides to already active slider. First there have been 4 slides rotating. Now I have added the fifth one, but even after refreshnig the page the fifth slide is not visible on the website. I checked the slug, visibility status, everything. I am kinda lost in here… thanks for your feedback.
Kaya
http://powerking.sk/energeticky-napoj/