High-quality video calls
To enable high-quality video calls with Skype for Mac, first download the latest version of Skype for Mac. You need version 18.104.22.168 or newer.
Then, quit Skype, navigate to "~/Library/Application Support/Skype/yourskypename/", i.e go to your home folder, and then the Library folder in it, and then Application Support in Library etc. Find the file called config.xml. Open the file and find the <Video> block that is itself inside the <Lib> block. The <Video> block probably looks as follows.
Now, edit this <Video> block, adding capture height and width settings. The block should now look like this.
Save and close config.xml, restart Skype and do a video call. The remote party should now see your picture in 640x480 resolution, instead of the standard quality 320x240.
Note that both parties need a fairly high-end computer (Mac or PC) to get good quality and framerate, plus a good Internet connection.