Images in different location

'm as new as it get to the whole web site building:

I created a web sit on my Mac Laptop OX 10.6.4 and the pages with images in viewing area show the images where I intended for them to be and everything look fine.

I transfer the web sit to my Desk top, which I had just now installed Mac OX 10.8.2 And the images in the web sit viewing area are at a completely different location … Any ideas on why this has happened? And how I might fix that?