Creating Text
First create a new image by going to File | New, set the width to 556 pixels and the height to 256 pixels. Select the Advanced Options menu and then ensure that "Fill with" is set to white. Then click ok to create the new image.
Next select Tools | Text and click an area on the left of the image. From the tool options, located in the tool box, select the font (type in the font box) and font size (e.g. 58) as required. Type your ebay user id into the text editor and it will appear in the image.
Rotating Text
Angle the text by going to Tools | Transform Tools | Rotate. In Gimp 2.6 the fulcrum, represented by the circle and cross hairs, can be dragged to any point within the image. Use this to set the point of rotation, drag the text or use the slider control to rotate the text to the desired angle then click on rotate.
Save this; File | Save, type in file name with extension (e.g. watermark.jpg). Clicking on save should produce a pop-up window, in this window select Export, in the next pop-up window set the Quality slider control to at least 85 and save it. Then close the image.
Embossing Text
Open the watermark image with the Gimp photo editor. Select Filters then
Distorts and click on Emboss.
In the pop up window use the slider controls to produce the required effect, this can be viewed
in the preview pane, then click ok. Go to File and save the image.
This process will leave a thin black border on both the left and right sides of the image. This is difficult to see but will show up in the watermark. This can be removed by using the airbrush tool. First select the Pick colours tool (the eye dropper) and pick/select the background colour. Then select the airbrush tool and carfully run the airbrush up both the left and right edges of the watermark image. Note; There may not be any noticeable change in the image.