if you use enumerations then you can display icons instead of text. For example you can create an enumeration with two items, YES and NO. Have a tick icon attached to YES and a cross icon to NO. In a data grid you can specify to show icons for the enumeration column.
Customising the style of individual cells, columns and rows in a datagrid is not supported yet. you might be able to do it with CSS though. I've requested this feature a while ago.
Hi Marco. If the answers to your questions are enumerations, you can define images corresponding to the enumeration choices and change the display type for the grid column to display the image instead of the text.
Alternatively, if the logo is say a company logo linked to the person completing the survey, you need to have an association to an image object (specialization of the System/Image entity) and you should then be able to include this if you use a Template grid instead of a data grid.