Most of the time you can simply crop the top right corner of the larger image to create the smaller image, which provides for a seamless transition between the opened and closed states.
Alternatively you can use the smaller image to display a call to action to entice users into interacting with the page peel.
Page peels are not served to tablet or mobile phone users so you don't need to give any special consideration to them.
Try not to use images that have the same or too similar of a background color as your page as it will spoil the page peel effect.
Quirks Mode Considerations
If your web site happens to render in Quirks Mode you will need to correct that in order for the page peel to show up correctly in Internet Explorer, however, this can usually be accomplished by simply specifying a doctype if one is missing or by switching to a standards compatible HTML doctype.
The HTML5 doctype as well as all of the XHTML 1.0 or 1.1 doctypes, which are the most commonly used for modern or relatively modern web sites are already rendered in standards compliant mode and require no changes.
On older web sites that use HTML 4.01 you must use the complete doctype with system identifier which would be one of the following:
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