Its generally not good practice to copy and paste pictures and other content from the internet into PowerPoint.
First make sure the image is not copyrighted – they often are!
Consider using a screen capture utility or otherwise
Right-click the picture, choose Save Picture As and save it to your hard drive.
To add the image:
Insert | Illustrations | Picture in PowerPoint 2007
Insert | Picture | From File in PowerPoint 2003 .
When you copy paste from the net, you may create a hard-to-remove link to the internet from your presentation. (Try a right mouse click and select rwmove hyerlink)
If nto removed then this may cause Windows to try to connect to the internet every time anyone opens the presentation.
Don’t link images
When you insert pictures you may notice an option to Link to the file. Unless you have a good reason for doing it, don’t. PowerPoint’s image links break very easily. It’s generally safer and more effective to embed the files (in other words, insert them normally, not linked).