By default, all cells are editable. All cells in Widget["DisplayOnlyTable"] are noneditable.
By default, most data stored in tables will be strings and left-aligned within the cells. However, it is possible to store, display, and retrieve Booleans, numbers, and images within table columns with more native controls using checkboxes, right-aligned text, and icons, respectively.
To display images, you will need to set "columnEditable" to False to avoid corrupting the original images.
It is important that all data within a given column match either the first row's types or the "prototype" property types if specified, because tables currently do not support rendering different data types on different rows within the same column.