If you can read this, you have very good eyes.
One tip when you come across pages like this one (they are unfortunately far too common) is to highlight the text with your mouse, which makes it temporarily visible.
Not all images can be used as a background for a webpage. This is a far too common mistake of new page designers. High-contrast, or large images rarely contribute to a web page, but often make them impossible to read. Keep background images subtle. They should not be very noticeable. The newest trend in web pages is actually a return to no background image at all, but rather a plain white or colored background.