i have huge nipples (ridiculous size really), my poor daughter could only get half of them in her mouth when she was feeding. they really do come in all shapes and sizes; but i don't think you should have a problem breastfeeding with small ones - it really is only the middle 'lump' that the baby's use. it may just take you a little while to figure out the best technique for you. as for the 'crack', that doesn't seem too abnormal either.

if you are worried, maybe you should ask your doctor, who has undoubtably seen plenty of nipples in their time. but i found breastfeeding has a lot more to do with the baby then where the milk comes from.