You maybe want to add image or icon like magnifiying icon in textInput of your flex, Here i have some method how you can do that :

Create AS Component

package nebula.utils
{
  import mx.controls.Image;
  import mx.controls.TextInput;
  
  public class SearchTextInput extends TextInput
  {
    public function SearchTextInput()
    {
    }
    
    override protected function createChildren():void
    {
      super.createChildren();
      var searchImg:Image = new Image();
      searchImg.source = Images.search_icon;
      searchImg.width=12;
      searchImg.height=12;
      searchImg.x = 2;
      searchImg.y = 3;
      setStyle("paddingLeft",searchImg.width+2);
      addChild(searchImg);
    }

  }
}

in mxml component you put this:

<utils:SearchTextInput text="enter professional name ..." id="searchPro" click="{searchPro.text = ''}" width="200"/>

Another Alternative (sometime not work)

<mx:HBox>
  <mx:TextInput id="myTextInput" />
  <mx:Images source="{your_image_url}" paddingLeft="6" />
</mx:HBox>