Recently added “echo_link” attribute open new doors of using this plugin. I will explain them here
1. Although, this plugin already has option to choose a custom payment button. But, if it does not comply with you situation you can use same shortcode like following
<a href="[paypal_button name="ABC Product" amount="10" echo_link="1"]"><img alt="" src="http://xyz.com/linktoyourbutton.png" /></a>
2. To open payment page in a new window you can use the same above code with additional one attirbute i.e. traget=”_blank”
<a href="[paypal_button name="ABC Product" amount="10" echo_link="1"]" target="_blank"><img alt="" src="http://xyz.com/linktoyourbutton.png" /></a>
3. If you just want to have payment URL so you an use it anywhere. For example, some themes, plugins, shortcodes and widget require a payment URL that have to start with http:// then I believe there is no other way around except to generate a PayPal payment URL from the shortcode and paste it to the field.
For example. Write following in any of your post (in Text view) after setting the proper attributes of your payment
<a href="[paypal_button amount=10 echo_link=1 name="ABC"]">Buy Now</a>
Then Visit this post and copy the link of “Buy Now” (right click on the URL and select “Copy Link”)and paste it where you want to put the Payment URL (starting with http://”). Copying URL from browser’s location bar after clicking on the link would not work. You have to copy by right clicking on it.
Link to default PayPal buttons are as below, just in case, you need them