To make a thumbnail image attractive a user can give width and height to thumbnail image. It is very easy for a user to insert width and height of image.Here some steps are give to insert width and height of image.

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To insert width and height of the feature/thumbnail image follow some steps.
Step 1 First click on Manage Templates menu of WP Post Pro Plugin,a list of templates will display in new window.
Step 2 Now click on Edit link of template you want to hide thumbnail.
Step 3 Scroll down on Featured Image Settings section and give the width of image in Thumbnail Width and height in Thumbnail Height.
Step 4 Now click on Save Template button at the bottom of the page.

Here the width of thumbnail is 20% and height of thumbnail is 30%.
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Video Tutorial