As I said before, the cells will all expand to fill the entire screen. If you don't want this done, edit the Screen Properties and uncheck the "Stretch layout" option.
Internet Explorer is rendering the screen, so it's up to IE to decide how to fill the screen. My observation has been that every cell will have its width and height increased proportionally until the screen is filled.
For example, if you have 3 columns and their content widths work out to be 100, 200, and 300 pixels wide, then of course the 3 columns will need to be 600 pixels wide. If your screen is 1200 pixels wide, then your 3 columns will fill up exactly half of the screen. To make the 3 columns fill the screen, the 600 available pixels could be divided evenly among the 3 columns (200 pixels each), making the columns now 300, 400, and 500 pixels wide. But this is not how it's done. Instead, every column will be twice as wide: 200, 400, and 600 pixels, so they remain the same size proportionally to each other.
This is essentially why extra space is being added "around" those Logo images. The trick isn't to "shrink" those cells so they are only as tall and wide as the images inside of them, but rather to make other cells wider or taller.
If the Logo cells were only as wide as the Logo images inside, where would the extra space go? To the column holding the Player images, and to the column holding the clock and the blinds. So instead of trying to narrow the Logo cells, widen the Player and Clock columns.