How can i make photo's(jpg)format smaller when saving to PC.?

Whenever i download photo's off my digital camera onto my PC, i save it in jpg file format. However it is often well over 300mb, and i have noticed that when friends send me their photo's the sizes vary from 70-90mb.So i am wondering how to save the photo's to be smaller!!Please help!!

I find questions of size of digital photos often confusing. Certainly no expert. But just a couple of details: I think the sizes you refer to (300) and (70 - 90) will be kilobytes (kb) not megabytes (mb). :-) [That was a quick reduction.]
The other point is that reducing the size of a digital image usually loses some information (as well as compressing with JPEG). 70 - 90kb is OK for internet use (emails, web sites, where high resolution is just wasted), but one day you might want full-quality such as for real-photo enlargement. Hence I suggest always making reductions copies and slightly adjust filename to indicate reduced version.

when saving jpgs save them in the paint format will downsize your photos but you will lost no quality

You need to adjust the size or crop the photos to make them smaller.
You can usually do it with the picture software that comes with your digital camera.
You can also download free picture editing software to do the same thing. I'd recommend this one:
http://www.gimp.org/

Simple image editing software should be able to do that for you. In fact, the CD that came with your digital camera should have included not only the software to make your camera talk to your PC but also a basic image editing software. There are some good, simple free programs at www.download.com. Look in the digital photography section on the left side of the page.
(By the way, your camera can be set to produce smaller images. However, this often means sacrificing the quality of the picture.)

hey , you can change your image size through Adob photoshop.and the new yahoo photo mail, you can adjust the size too . as you mentioned it must be 300 kb not mb .