I\'ve got an image that floats in the bottom right corner (to put in the button, the position has to be fixed). However, part of the text on my page disappears behind the image.
when you use a position fixed or absolute (float here is irrelevant for your style, you could remove it) you're removing an element from its natural flow. Thus, given this position, the text is not able to detect the image and to re-arrange itself around it.