nothing happens after changing files

i recently started creating a a website and and published it. i also installed themes plug ins and such. yet there is always something i want to improve and most of the time i am able to do it. but recently i tryed to put a image on a side bar with the url of my facebook page. it didnt work so i removed the widget from my side bar yet, when i refresh my web site the image is still there. it drives me insane. this also happens when i change some code from the theme… the new changes i make just dont appear.

i have tried to clear my cache and the cache of my web browser but … the picture is still there . it literally drives me nuts.

i just want to know why this problem appears and hopefully how to fix it. any help would be appreciated. cheers