Looking for a hack to resize images on upload (all forms of image uploads on wordpress) to exact dimensions, but not to crop.

I will open a bounty for this question since I believe It can be of help for a lot of people.

The ideal solution must be as a plugin and using the image dimensions already specified on the Media Settings Page (options-media.php / Thumbnail , Medium and Large)

I know the ideal sometimes can't be done, so the closest answer will be the accepted one

1 Answer 1


Custom Image Sizes

Resizing without cropping is already part of the core functionality, via add_image_size().

Note the last parameter:

<?php add_image_size( $name, $width, $height, $crop ); ?>

The Codex entry describes the $crop parameter as follows:


(boolean) (optional) Crop the image or not. False - Soft proportional crop mode ; True - Hard crop mode. Default: false

I prefer to describe the option as hard-crop vs. box-resize. Hard-crop will crop the image based on the most-restrained dimension, whereas box-resize will simply resize the image, retaining its original dimension proportions.

So, to create a box-resized image size, simply define it as follows:

add_image_size( 'image-size-name', $width, $height, false );

Note that this behavior is the default setting. In order to hard-crop, you have to explicitly specify $crop to be true.

Post Thumbnails

Changing the post-thumbnail image size to box-resize is similar; simply use set_post_thumbnail_size(), which also has a $crop parameter:

 <?php set_post_thumbnail_size( $width, $height, $crop ); ?>

Reserved Image Sizes

I'm pretty sure 'medium' and 'large' image sizes are already box-resized rather than hard-cropped.

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