How many columns are there in that grid and how many of them are image columns? Where exactly is the code you just posted located? How exactly is Form1 displayed? Why are you configuring the image column in code rather than in the designer?

On a more rhetorical note, why aren't you using descriptive names for things? You should have anything named Form1, ListBox2 or DataGridView2 in your application. Those names are meaningless when it comes to understanding what the things they refer to are actually for.