image size reduction

Hi, can anyone tell me how to reduce the size of my images so that i can upload them onto the gallery.

All my images are over 5mg so i need to reduce them down to 4mg or under, i am shooting in JPEG-fine.

I have got Lightroom and SC4 but not sure how to use either as yet.

Please help as i have loads of images to upload including a very hungry Heron.

cheers, Macro

Birds are not shy, they just like to make photographers look dumb.