I downloaded an image (.eps) from istockphoto, that contains several icons.
I cropped the icon I wanted from the image and saved it to jpg, using corel snapfire.

Then I uploaded to my web site's image folder and viewed it. And it looks jagged not sharp. I know if you enlarge an image it will start to look jagged, but I'm not enlarging it.

So, what am I doing wrong? The displayed image on the web page is smaller than the thumbnail from which I cropped it from.
How can I make the image look as sharp on my website, as it does in the thumbnail on my PC? I tried cropping and saving it as .eps and uploading, but it just showed the X, as in no picture appeared.

Thanks.

I'd have to see the images to even begin to know what is going on.

Try saving a different file extension. Jpeg is "lossy" or throws data away to make its compression scheme work more efficiently. If you're too aggressive with the quality versus file size, it would produce something like what you're describing.

Tiff and png files are huge, but lossless; give one of them a try to see whether this is your problem. If so, you need to figure out how to change the jpeg quality settings in your software.