Video quality issue using Skype

Model Name - iMac
Model Ident. - iMac7,1
os x ver. - 10.5.8
processor - 2.4 GHz Intel Core 2 Duo
Memory - 2 GB 667 MHz DDR2 SDRAM
camera - Built-in iSight
Software fully updated
speedtest.net results:
Download Speed - 14.08 Mbps
Upload Speed - 5.57 Mbps

Model Name - MacBook Pro 13-inch, Late 2011
Model Ident. - MacBookPro8,1
os x ver. - 10.7.5
processor - 2.4 GHz Intel Core i5
Memory - 4 GB 1333 MHz DDR3
camera - FaceTime HD Camera (Built-in)
Software fully updated
Speedtest.net results
Download Speed - 12.52 Mbps
Upload Speed - 5.43


I've begun to travel as part of my job, so my wife and I decided to use Skype when I'm on the road (and just to be clear, I take the MacBook Pro with me, and she uses the iMac at home). Our first try resulted in my seeing and hearing her perfectly, while she could hear me perfectly but could only see a poor video. Cleaning the screen over the built-in cameras didn't help.

When I got home, we Skyped each other from different parts of the house so I could see what she was describing. I, using the iMac, heard her perfectly, but the video quality was pixelated and blurry. She, using the MacBook Pro, could hear and see perfectly. If she waived her hand in front of the MacBook's camera, the video on the iMac would get dramatically worse and even freeze for a half second.

It appears there's some problem causing pixelation and blurring between the time the light enters the lens of the camera on the MacBook Pro to the time the video image is displayed on the iMac.

Is there anything I can do, like changing configuration settings or something else, to make the video on the iMac as good as the video on the MacBook Pro?

Just in case someone comes here looking for an answer, and since no one has given an answer here, I'm coming back to give an update. Since we're all "Mac Brothers" I hope this doesn't violate any policies, or is impolite. At another forum (Mac dash Forums​ dott com) another user, chscag, suggested three things: Onyx cleanup, memory upgrade, and Snow Leopard upgrade.

I downloaded and ran Onyx. I didn't realize how much my iMac needed in the way of maintenance. I actually had to use the dvd that came with the iMac to boot to the disk's disc utility to repair the disc.

Then, I got two memory cards and upgraded from 2GB to 4GB.

The picture is now as good as the MBP's, and there's no (or exceedingly little) pixelation/blurring.

I've ordered the upgrade to Snow Leopard, but if there's further improvement that will only be icing on the cake.