Go to C:\SCADA\ScadaWeb\images
Then just overwrite the images.
Also you can change css styles in *.css but is is not recommended because you should do the same task when a new version released.
Add the files in the application directory (for example, C:\SCADA\ScadaServer):
The content of About.txt:
232 174 95 23
There the numbers are X, Y, width and height of the link.