Images and tables can be sized according to pixels, or percentages. With pixels, the image or table is a fixed size. When viewed on a phone or tablet, the image or table will be shown in full, but the text in Web Presence Display Messages may be very small, and require zooming in.
With percentage, the image or table scales based on screen size - from a smartphone to a desktop computer, text is readable, and the image is appropriately-sized.
To have images scale based on screen size, highlight the image > Insert/Edit Image. Set Width to any percentage between 1% and 100%, or enter "auto".
To have tables scale based on screen size, select Table > Table Properties > Set Width to any percentage between 1% and 100%, or enter "auto".
After adjusting, view the web page on a desktop/laptop and a smartphone, to be sure it looks right on both. Edit the dimensions, if needed.