Sprites are automatically drawn over text. To work around this you would want to paste the sprite to the screen instead of drawing the sprite to the screen. Like this:
load image "sixDisplay.png", 96
sprite 96,0,0,96
hide sprite 96
do
printScreen()
paste sprite 96,100,100
text 120,125,"sixDisplay Here"
loop
function printScreen()
load bitmap "BG.bmp"
text 180,195,"fiftyDisplay Here"
endfunction
You also don't need to load images every frame. You can load your image once before your main loop to hold it in memory. The only time you need to load it again is if you delete it.