Something is big if it is many times larger than something else. The ship in the picture is much bigger than the little boat at the front of the picture. The opposite of big is small.
A person or animal is blind if they cannot see. People who are blind can still live very full lives. They can read books written in braille and can travel around with the help of a white cane or a seeing eye dog.
Something is described as blunt when it is not sharp compared to something similar. For example, butter knives are blunt and steak knives are sharp. Baseball bats are blunt and swords are sharp.
The photo is of some blunt pencils. Pencils are hard to draw with when they are blunt.