A vector graphic can be resized without losing the quality of the graphic. In LibreOffice Draw and Impress, you can convert a bitmap image into a vector graphic.
Select the bitmap image that you want to convert.
Do one of the following:
In LibreOffice Draw, choose Shape - Convert - To Polygon.
In LibreOffice Impress, right-click the object, and then choose Convert - To Polygon.
Set the conversion options for the image, and then click OK. See Convert to Polygon for a description of the conversion options.