How Should WordPress Sidebar Ads be Sized?

I had never posted a sidebar ad before.

FOR PURPOSES OF TEST I created a sidebar ad graphic of size 300 pixels width by 250 pixels height.  Then I placed it in a number of different types of sidebar widgets.

• Some of the widgets RESIZE the image!
• Some do not!

IMPORTANT QUESTION: Is it best to size sidebar ad images to dimensions such that they won’t have to be resized by WordPress?  Does this result in crisper more appealing images?

The “TEXT” widget, “CUSTOM HTML” widget, and “EXTRA ADS” widget all resize the image.

Whereas, the “IMAGE” widget, the “MODERN TRIBE IMAGE” widget, and the “ADVANCED ADS” widget DO NOT resize the image.

 

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