As mentioned above, your Achhiles heel are keywords. For example your titles "woman" can't work. Look at small stats which illustrate Afagundes words: woman: 1,769,919 images in database student: 187,437 images in database student library: 11,856 images in database
I think it is better compete only 11 thousands images than one and half milion.
Here's a video interview with Dreamstime admin Carmen Pietraru (aka "Tangie") about keywording, descriptions, and titles. This is from a few years ago, but it is still quite useful. Just before minute 4:00, she mentions that short titles are good; when pressed, she indicates that 3-5 words would generally make a good title. In the video, she explains how lots of keywords helps and how it hurts. Enjoy -- Interview with Carmen Pietraru