Make any other changes you require such as adding text. Remember this will appear as a background which you don't want to distract from the other items on the page. Make sure that the texture is selected. This dims the other options. Otherwise you have to select a quality setting.
Lower settings give greater compression but lower quality.
We suggest saving the file then viewing it in a browser . If the quality loss is noticeable, save the file again with a higher Quality setting. Alternatively, if the file size is too big, save with a lower Quality setting. The best setting depends on the particular bitmap. For example the center bitmap at the top of the page has more detail and needed a higher quality setting than the other two.