Use free website that allow you to shrink your images and make them web friendly.
- ShrinkPictures
- Smush It
- Image Optimizer
- GIFBot
- Web Resizer
- Dynamic Drive Image Optimizer
- Online Image Compression
- iResize
- PunyPng
Please read the following article that provides more detailed information Top 10 Free Online Tools to Reduce Image Size for Web
