i changed image on dreamviewer but no change in browser..help :(

hello friends,
i don't know if it is a right place to ask but i guess there are alot of coders and expert web-designers are here in this forum so definitely those can help me a little bit, i will be always grateful for your help & kind.

i am customizing my website through adobe dreamviewer CS6, though i am just a noob and don't know much coding but still on way of learning, so with the help of you peoples i can improve my learning skills.

I'm trying to edit a slider images of my website using dreamweaver CS6 which is apparently supposed to be easy  i edited the text of slider images in photoshop and putted it in a right folder where it should be.
The modified image shows up on dreamweaver properly, but in web browser i am seeing the same non-edited image even i replaced the old image file with new one on the server via ftp.
why it is happening, i can't figure out.

this is my website : Ultimate Hosting Solutions

you can see the slider, the text which is appearing has been changed already and uploaded to the server but don't know how the old sliders is still coming.

Any suggestions....I'm new at this
Thanks!