This picture is a good example of Hijab. The image in the left represents a modest Muslim woman wearing the Hijab and the image on the right represents a woman not wearing the Hijab. And the flies are men ;)
One thing should be kept in mind. The Hijab is given the wider meaning of modesty, privacy, and morality. The hijab is not ment only for the women. Its also ment for the men as well. Infact in the Quran ALLAH speaks about the hijab for the men first and then for the women.
Say to the believing men that they should lower their gaze and guard their modesty: that will make for greater purity for them: And Allah is well acquainted with all that they do.
[Quran: Chapter-24, Verse-30]
And Say to the believing women that they should lower their gaze and guard their modesty; that they should not display their beauty and ornaments except what (must ordinarily) appear thereof; that they should draw their veils over their bosoms and not display their beauty except to their husbands, their fathers, their husband's fathers, their sons, their husbands' sons, their brothers or their brothers' sons, or their sisters' sons, or their women, or the slaves whom their right hands possess, or male servants free of physical needs, or small children who have no sense of the shame of sex; and that they should not strike their feet in order to draw attention to their hidden ornaments. And O ye Believers! turn ye all together towards Allah, that ye may attain Bliss.
[Quran: Chapter-24, Verse-31]