pdf file reduction

You can try to save your PDF as an optimized PDF, choose zip compression, do not downsample, to retain maximum image quality. You can also select discard objects, which might reduce the PDF overhead without affecting the images. If it's still too big, upload it to Dropbox, or some other site and email a link to it.

Here is a link to a recent discussion about compression you might find useful:

Weight of PDF differs depending compression of placed image

A document created in Photoshop can be saved as a flattened eps file, then brought into Acrobat distiller. This will create a lower resolution pdf that can be emailed.

If the file only contains images, how do you expect to be able to reduce its size without reducing the image quality?