Clip Art Problems

I am trying to insert clip art into a powerpoint. I went to insert clip art and couldn't find any picture i liked so I went to get clip art online. However, after I downloaded the picture onto my desktop, the picture wouldn't open and I had microsoft word 2004 and powerpoint running. The alert that popped up told me Clip Gallery must be opened in Office. I found out that the file is a microsoft clip gallery database. I want to the picture to appear in my clip art so i can easily insert it into my powerpoint. All I did was download a picture. Before it downloaded it asked me what I would like to open it with, but nothing happened. My operating system is Mac OS X 10.4.10. This is frustrating me! Please help