TAdvGrid - Picture in cell (HTML)

I try to insert a picture in a cell with this statement:
TabellaControlli->Cells[1][TabellaControlli->Row]="Questo funsia? <IMG src=''idx:2''";
but doesn't appear nothing, only a text.
I've declared a PictureContainer and link with AdvGrid.
Where is the error?

When using the idx: attribute, this referes to image 2 from the imagelist assigned to grid.GridImages