This is done in Photoshop but the image created can be used on a web page.
You can fill text with an image by applying a clipping mask to an image layer placed above a text layer in the layers palette.
In PS open the image you want to use.
Select the text tool you want (horizontal or vertical) and open the character tab (If it is not open choose Window > Character) Choose the font and size you want to use: large, bold, thick letters work best.
Click an insertion point in the image window and type the text. When ready, ctrl+enter (Windows) or cmd+return(Mac)
Click the layers tab to bring the layers palette to the front. (Window > Layers to show Layers palette)
Optional: If the image layer is the background layer, double click the image layer in the Layers palette to convert it from a background layer to a regular layer. This is because background layers are locked so it is necessary to convert them to unlock them. You can rename the layer.
In the Layers palette drag the image layer so that it is immediately above the text layer.
With the image layer selected, choose Layer > Create Clipping Mask. The image appears inside the text.
Select the Move tool and drag the image to adjust its placement within the text, or select the text layer in the Layers Palette and use the Move tool to move the text.
Crop the text image you have created and save it. Optimise and export it to your web site using Save for Web
To use on your DW page: drag the image to the page from the files list or use Insert
Note: In some versions of Photoshop to make an image as above you Make a Clipping Group, instead of creating a clipping mask, like this:
Hold down Alt (Windows) or Option (Mac OS), position the pointer over the line dividing two layers in the Layers palette (the pointer changes to two overlapping circles), and click.