A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Excel all by itself doesn't support what you are trying to accomplish. Pictures in Excel are in layers above the grid. There's no way to make the part of the grid itself, so they are floating above the grid and can be positioned and resized to appear as if they are in the cells.
If I were doing this I would use Excel as the data source for a Word Mail Merge that uses the INCLUDEPICTURE Word field. In Word, pictures are able to be included in the grid of a table. I would use a column in an Excel workbook to store the complete file path to each picture that is to be displayed.