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So we need determining where the negative cy may comes from.

At first: You should not using constants for BIG_CELL_COLUMN_WIDTH_IN_PIXELS and BIG_CELL_ROW_HEIGHT_IN_PIXELS. Instead do the same as apache poi does and use sheet.getColumnWidthInPixels and ImageUtils.getRowHeightInPixels to calculate width and height.

And you need set row height according to the fonts height. Else the row remains in default height until Excel is rendering the sheet in view. And in default row height, the dy1 is outside the row if greater than 190500. So it would not be a valid dy1 for this row.

There is private CTTransform2D createXfrm(XSSFClientAnchor anchor) in XSSFDrawing.java which calculates the xfrm containing the cy. There you can see, that a negative cy only occurs if height + anchor.getDy2() is lower than anchor.getDy1().

Using XSSF this would be enough. But using SXSSF the calculation of the row height in private CTTransform2D createXfrm(XSSFClientAnchor anchor) using ImageUtils.getRowHeightInPixels(sheet, row) seems to be wrong. I suspect this is because row height is not known already in the sheet because of the streaming manner. So we need a workaround. Set default row height that big as needed for the big font, set the picture then and reset the default row height after that.

The following works for me:

I believe you need to create bitmap image data from stream first

There's a solution already for that here on Stack Overflow: Byte Array to Bitmap Image I copy-paste the code from the solution: