Tap again to bring up menu: Insert > Tap the “+” at the top of the screen > Image > Image in cell
Select an image from the options presented to you.
Additional details
You can have multiple cells containing an image in a Sheet, but note that only one image per cell is possible at the moment.
Images inside cells will be associated with a row and move along with the data—so, if you move rows, filter or sort them, the images will move with the content in the row, unlike previously when images would sit on top of the grid.
Using the formatting and alignment tools, you can pin the image to a specific corner of the cell or set the alignment how you’d like. By default, images will align to the bottom left corner of the cell.
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