Display first page of PDF as Image

I am creating web application where I am displaying images/ pdf in thumbnail format. Onclicking respective image/ pdf it get open in new window.

For PDF, I have (this is code of the new window)

<iframe src="images/testes.pdf" width="800" height="200" />

Using this I can see all PDF in web browser. However for thumbnail purpose, I want to display only first page of PDF as an Image.

I tried

 <h:graphicImage value="images/testes.pdf" width="800" height="200" />

however it is not working. Any idea how to get this done?

Update 1

I am providing path of pdf file for example purpose. However I have images in Database. In actual I have code as below.

<iframe src="#{PersonalInformationDataBean.myAttachmentString}" width="800" height="200" />

Update 2

For sake of thumbnail, what I am using is

 <h:graphicImage height=200 width=200 value="...."> 

however I need to achieve same for PDF also.

Hope I am clear what I am expecting...