Am I able to change the size of a photo after I put it on my pc from my digital camera?

I would like to upload a photo that I took onto a website. I took the pic with a digital camera then loaded it onto my computer. The website said the file size was too large. Is there a way to compress the file or make it smaller? Thanks!

Download and install the freeware IrfanView, it has many useful features, yet is extremely easy to handle. Once it is installed, open your pic with it, go to "image" in the top bar, click "change size", enter the desired size, also change the DPI (dots per inch) settings to 72, then save your pic as .jpg or .gif. By downsizing your pic, saving it in a lesser format and also reducing the DPI settings, you may keep quite a few people from stealing your pictures, as they still look good on the site, but when you try to enlarge them or print them, the quality will become blurry. That's why you should keep a copy of the original high quality on your computer!

http://www.irfanview.net/

Here is a free on line photo resizer i have used it and found it easy to use and offering a good free service. no software download needed.
http://webresizer.com