OK Never mind the link below as the pictures are AWOL.
Go into overload and flip to the label tab, and change the two sizes. (5 and 2.5 if you maxed it out with the slider) This is just the size of the box not the picture. Picture size is with fontsize.
You can change those number and whittle it down to the right size after you get it bigger.
From the forum post:

NOW YOU NEED TO MAKE THE STICKER FIT THE PICTURE. USING WIDTH AND HEIGHT.

YOU MIGHT/WILL NEED TO DO THIS MULTIPLE TIMES TO GET THE PROPER FIT. TOO BIG AND IT IS CONSTANTLY GETTING MOVED IN THE BUILDER, TOO SMALL AND YOU GET A MESSED UP PIC/STICK/LABEL.
YOU CAN RESIZE, USING OVERLOAD OR FINER TUNER, THOUGH IF YOU PLAN ON CURVING THE STICKER, THE FONT SIZE NEEDS TO BE HIGH AND THEN RESIZE DOWN IN OL, PART TAB, I.E. SCALE 0.2,0.2,0.2

I will help

Edit, The old delta logo, the black and red one.