Image sizing problem

I have an image background in my site which is 1000 x 1000

I am tring to replace it with a new image the same size. I found a resizing image site, but when you increase it to 1000 x 1000 to cover the screen available, it is out of focus on the screen. Is there any advice you can provide on converting smaller images to 1000 x 1000 without losing image focus?

Many Thanks

If you're trying to take an image and reproduce it at a larger size, it won't work....

Generally, enlarging images will decrease resolution and, as a result, the images will become blurry...

On the other hand, reducing large images to a smaller size will not result in any loss of resolution (it might increase the resolution, I'm not sure)....So your images will still look OK this way...

Moral of the story: You need an original image that is at least 1000 x 1000, or higher. Or you need a smaller image with a very high resolution (i.e., 300 DPI - 600 DPI), so that when you enlarge it, the resulting resolution is still at least 72 DPI (dots per inch) or higher (screen resolution)...