Help With Slicing.

when you use "Save For Web" in adobe photoshop CS2 and that window comes up (dont know what its called) and then you can slice it and stuff for the web and select save settings.. well is there a way so that when you have saved it it will center it instead of doing the most annoying thing ever and coding it and slicing it all to the left of the page ?
its so annoying..
if not then could you give me the ocde to put around each image tag so that i can center it please ? i think i need to get round this stage before i can start adding tables dont you think ?

Thanks for the help!