Does it say in the Bible a woman should only wear dresses?

Answer:

I know of no place in the Bible it says this, although women are given instructions on how to make themselves beautiful, dress, and teach younger women to be respectable…

Titus 2:3-5  The aged women likewise, that they be in behaviour as becometh holiness, not false accusers, not given to much wine, teachers of good things;  That they may teach the young women to be sober, to love their husbands, to love their children,  To be discreet, chaste, keepers at home, good, obedient to their own husbands, that the word of God be not blasphemed.

1 Peter 3:1-6  Likewise, ye wives, be in subjection to your own husbands; that, if any obey not the word, they also may without the word be won by the conversation of the wives; While they behold your chaste conversation coupled with fear. Whose adorning let it not be that outward adorning of plaiting the hair, and of wearing of gold, or of putting on of apparel; But let it be the hidden man of the heart, in that which is not corruptible, even the ornament of a meek and quiet spirit, which is in the sight of God of great price. For after this manner in the old time the holy women also, who trusted in God, adorned themselves, being in subjection unto their own husbands: Even as Sara obeyed Abraham, calling him lord: whose daughters ye are, as long as ye do well, and are not afraid with any amazement.

God is more concerned about what is in your heart than what is on your body, although anything you wear should be worn to glorify God and not your own body (otherwise, be modest J)