> Hi, I wanted to download only images from a site, but the 
> images are hosted on different server. Can you help me 
> step by step, since I'm a noob :)

Just include proper filters (scan rules) and mirror the 
website with default settings:

Go to "Set Options"
Then, to "Scan rules"
Copy these rules:
+*.gif +*.jpg +*.jpeg +*.png +*.bmp +*.tif +*.tga

And then start the mirror as usual.

(note: include more scan rules if necessary)