Rift Raid Progress Widget is a raid progress tracking widget.
To change the images, you'll just need to change the images in images folder. Look for the images with underscores in them. for example "images/dh/dh_.png" If you do change them make sure you keep the png file format.
To change the css for the popup tooltip look at the tooltip.cs background-color - to change the colour of the background color - to change the font colour.