First up welcome aboard Danger [righton]
Once upon a time [bustagut] [bustagut] [bustagut] nah a long time ago I wrote this pdf for someone expaining how to create a basic sliced up site in PS......... she had to add roll overs etc which is why I have in the instructions to jump to IR - for now do this also because...........
As Tranquil asked......... how can you save some slices as gifs and some as jpg's ........ you will find in IR that if you use the slice selection tool you can hold shift then click on the slices which is selecting the slices that you want to save as gif's then go up to ...... slices/link slices then on your optimise pallet you can select jpg or gif set the quality etc now all of the slices that you linked together will be the same format (jpg or gif) and the same quality - hope that helps [righton]
Danger try opening and starting again in ps with your photo
place your guides where you would like to slice your image then go to file/jump to IR
http://www.sitedezigns.com/step-one.pdf
well I hope it helps anyway
sfm