Bronze Corydoras Gender

Could you please help me sex these corydoras?

#1-(I don't know)

#2 - (female)?

#3-(male)?
If you need a clearer image do not hesitate of any catfish to ask me!

Discerning the gender of Corydoras is not easy; females when viewed from above will be rounded while males are slender. In a very few species, one of the paired fins (pectoral or ventral, cannot remember) can be more rounded in females but cory experts say this is usually impossible to really see. The interactions among the group can sometimes point out males who will be nudging and "following" or "pushing" females, and assuming the "T" position, but unless the fish are in spawning mode this may not be too obvious.

There are no external differences between genders.