Why are there so few images of naked men worth seeing?

I run a tumblr with well over 40,000 images and a city of followers.

Over 98% of the images you will find there are of women. Usually naked women.

Updating my tumblr daily as I do requires work. The sheer volume of available images of naked females makes my job relatively easy.

Why is the ratio of good images of the naked male form so unbalanced?

Amanda