Choose the caption bubble to begin. If you want to upload a custom bubble or alternative image then submit the caption first, then edit the comment and attach a "Place img". Once the image is approved you can use it by editing the caption again.
It's not like it's hard to shave between your eyebrows, but maybe it's some retro hip look to have the appearance of a neanderthal where he lives... but then we're really stretching retro here.