Okay, I've downloaded and installed it with no problems whatsoever.
Is it possible that an Anti virus program prevents you from opening it??
If you get it open, go to "File>Open..."
Browse your computer to locate the file and open it.
Then go to "Edit>Edit Image...."
On the right side you will see the word "Resize" which will offer you options for pixle and percentages.
When you are finish, go back to File>Save as...
Give it a name and choose "Compu Serve GIF (*gif)"
And that's it.........

__________________

"Never Argue With An Idiot. They Will Drag You Down To Their Level, Then Beat You With Experience"