Saving Images in png format in Photoshop makes it blurry when used in websites

If you are using shapes/vectors, try and line them up to the nearest pixel. PS will use antialiasing to round it off, so if your shape/vector lines are sub-pixel, it will make a semi-transparent pixel on the edge to represent that 'half way in between 2 pixels'.

This is also a common issue when down sizing an image. It helps to keep the original size as a multiple of the smaller. Make it x2 or x4 to get cleaner edges when downsizing.