You can load the image within the URL saved in the cell value and draw ImageCellRenderer. If the cell value does not have the full path, you can use valueCallback of Calculated Column to dynamically create it as below example.
You can specify how to draw the image in the cell through ImageCellRenderer.imageDisplay property. In the example below, the constant value has been displayed in image column headers which is specified by ImageDisplay constant.
You can draw the image renderer with using iconAlpha.
Change iconAlpha style of the image columns.