Hi pheebs - yes 4 mb is a large file with high resolution. Did you know you can get the same quality digital picture by using a lower resolution on your camera.
For email and website purposes, 2 megapixels is plenty, maybe even a little too much. If you want standard 4 x 6" or even 8 x10" prints this is also enough. When you use higher resolutions, you can have larger prints up to 20 x 30". Higher resolutions also allow you plenty of
leeway to crop your digital pictures. So unless you need large prints or need to crop your image, using lower resolutions settings (or megapixels or quality) on your camera is one way to reduce the size of your file (picture).
Another way to reduce file size for email purposes etc can be found in
iPhoto. You can do it 2 ways, one is to Share > Email > you can choose small, medium, large or orginal size. Second method Share > Export > Scale images to your liking...
The last method involves an image editing software of your choice. (Mine happens to be
Graphic Converter) You can save your images at it's current resolution but at a slightly lower quality, called optimization, using this method in a good software can yield upto 80 to 95% reduction on file size while keeping the same resolution. This type of App will also let you crop, resize, and edit most digital images...
Hope this helps, best wishes on your project, Rick
iMac G5 iSight 20" - 30G iPOD - HP Pav 15" WS and Toshiba Sat 17" WS Mac OS X (10.4.7) Canon 20D & A620