You can put the player's X and Y position in two separate variables, then modify these variables as explained below, then use these modified variables for the picture's position.
The player's position is expressed in tiles, while the picture's position is expressed in pixels. A tile is 32 by 32 pixels. Thus, to place the picture just below the player, the position of the upper-left corner of the picture will be X = player's X position * 32 and Y = (player's Y position * 32) + 32
If your picture is the size of a tile (32x32 px), then you can just go with the formula above. If your picture has a different size, a little bit of tweaking might be required.
Edit: Wow, didn't realize this thread is one month old already.