What you will want to use instead is the advanced text block to do this. You will want to make sure that you are using Firefox when you do this.
The first step is adding a new block, Type: Text-Advanced (it is near the bottom of the drop down menu). Then you will put in your picture. (To insert a picture you will click on the picture icon it is near the middle right above Font Size). Then once you have added a picture you will click on the picture and add a hyper link. (To add a hyper link you will select the chain icon that is to the right of the picture icon). You will put in the link information and then under Target: You will select blank.