Image cropping adjusts the size and aspect ratio of an advertisement image to fit the available ad space on a web page or mobile app. The goal of cropping is to maximize the visibility and impact of the ad while ensuring that it does not look distorted or truncated.

This process is automatically done by Zemanta’s default automated system called Optimized image cropping which uses algorithms to take into account the available display space, the aspect ratio of the ad image, and other factors such as the importance of different elements in the image. However, you can also select other image cropping options, depending on your needs.
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When uploading a creative the default cropping option selected is Optimized. When the Optimized option from the dropdown menu is selected either by default or manually, our system will automatically enable the algorithm to find and bid on ads by using the best cropping strategy (selected from the options in the drop-down menu) of the ad placement based on bid request. If the ad group does not get enough volume, the strategy that works best on average will be applied to the placement instead.

PLEASE NOTE: The Optimized value does not differ from other image cropping options but it simply selects the most suitable image cropping option for your image.

Crops and moves your image so that its central portion is displayed. This allows the image to fit into a specific aspect ratio or size while maintaining the most visually important part of the image.

If any faces are detected in the image you uploaded it crops your image to include the face region of the image and moves that region to the center. The goal is to create a standardized and consistent representation of the face to appear in the ad space.

Entropy aims to crop an area of interest that includes the most information-rich or busy part of the image while avoiding areas of low entropy such as solid color backgrounds.

Crop from the left of the image to the right.

Crop from the right of the image to the left.

Crop from the top of the image to the bottom.

Crop from the bottom of the image to the top.

Resize your image to fit within the requested width and height dimensions while preserving the original aspect ratio and without discarding any original image data. Excess space is filled with a blurred version of the image.

Another good recommendation is to place the important part of the image in the center. In this way, you avoid possible problems if the important part of the visual is cut off because it is too close to the borders.

Example of the original (plausibly problematic) image where the important part of the visual is close to the borders of the image:

Image with the important part of the visual moved from the borders (to the center) and "zoomed-out":

In this example, you can see that when the image has the important elements of the visual more towards the center and not close to the borders, different image ratio crops will preserve the important part of the image.