I believe that is what the set_post_thumbnail_size function is for.
Set the default Post Thumbnail dimensions. To register additional image sizes for Post Thumbnails use: add_image_size().
See http://codex.wordpress.org/Function_Reference/set_post_thumbnail_size
Related Posts:
- How to get image title/alt attribute?
- How to disable WordPress from creating thumbnails?
- How do you get the post thumbnail size?
- set_post_thumbnail_size vs add_image_size
- Minimum Dimensions Requirement for Featured Image?
- Generate Thumbnails only for Featured Images
- How to get all featured image sizes and their URLs?
- How to Dynamically Resize WordPress Image On-The-Fly (custom field/theme option)
- Display thumbnail only if requested size exists
- the_post_thumbnail responsive srcset not populating with custom image size
- How to add multiple image sizes of the same size with add_image_size
- New image size version only for the Featured Image file
- Can’t extract and set SVG dimensions
- Getting custom-sized featured image’s URL?
- Showing a placeholder/default img, if no featured image is set
- Featured image with the same height thumbs returns wrong thumb
- How to change the naming of the resized image files
- Change Output for Images in Content
- Can WordPress crop only the post thumbnails?
- Allow user to manually set crop area of default/custom image sizes on upload [closed]
- How to get the image sizes, in a function, as per the sizes mentioned in the media settings?
- Resizing Images to lower Disk Space Using Plugins
- How to change _wp_attachment_metadata specific value in SQL?
- Autogenerated Thumbnail compression depending on size
- Only create image size when used in featured image
- How can I get a different image size, if all I have is the link?
- How to get custom image sizes into media uploader dropdown?
- WordPress resizes image to the same size as uploaded
- add_image_size and add_filter(‘image_size_names_choose’, ‘my_custom_image_sizes’) not working with wordpress 3.5.2
- wordpress responsive image srcset not working
- Customising the size of images served in Visual Composer elements [closed]
- How do I get a random image from subset of images in media gallery?
- How to scale up post thumbnails/featured image?
- Why are extra 92 pixel square thumbnails created?
- wp-cli regenerate media is not working for custom sizes
- Upload 3 different featured image sizes to WordPress
- Remove dimensions from filename featured image
- Can a thumbnail of an animated gif be animated?
- WordPress Uploader Editor shows broken image
- add_image_size not working with the_post_thumbnail
- Why does the Hard Crop option Scale?
- How to get full absolute url for post attachment?
- Thumbnail Cropping with add_image_size?
- thumbnails are getting clipped down, want to resize instead
- How check that there is post thumbnail feature image or not on wordpress?
- If I Regenerate Thumbnails, would WordPress delete the existing Thumbnails and replace them with ‘new copies’?
- How to get cropped thumbnail source for custom post type
- Exclude featured image from attachment loop
- 2 image size for post
- adaptive featured images wordpress 4.4 grid
- Featured Image Not Working when loaded from sub-domain
- How can I see where in my themes and plugins certain image sizes are used?
- Generate image for newly added size
- How to both crop (with tool) and resize thumbnails having only a max width constrain?
- “Medium” size image displayed instead of “thumbnail” in only one post, other posts are fine
- wp_get_attachment_image_src match smallest edge
- How to create resized versions of images added with wp_insert_attachment
- WordPress returns old thumbnail size after changing media settings
- Custom image size in the_content loop
- remove and disable image link in functions.php
- specify size of post preview image (not post thumbnail)
- Display featured image file size, extension, filename, type, orientation?
- media-library: how to insert thumbnails with a fixed width, regardless of landscape/portrait orientation
- the_post_thumbnail(‘my_image_size’) always outputs full image
- Server B handling add_image_size() differently than Server A
- Post thumbnail throwing size limit parameters in
- Get thumbnail image according to the screen
- Image with large file size not cropping
- What can I do if I set a gif as featured image? no thumbnail when i share on facebook
- images not showing despite using add_theme_support(‘post-thumbnails’);
- Resizing thumbnails retrospectively
- Trying to show link “Use as featured image” from Attachment window from t31os script
- post thumbnail: increase dimension if smaller than… Possible?
- Images uploaded on frontend display correctly but not in media editor.
- Generating very small sized thumbnails from featured image
- Make image full width
- How risize a thumbnail?
- Unrestricted height thumbnails
- custom thumbnail image size not working
- WordPress not creating “large” thumbnails
- Is wordpress compressing my images? if so, how to prevent it?
- Custom caption output for custom image size
- Display post thumbnail in foreach loop
- How to attach images that I “insert from url” into the post?
- the_post_thumbnail(‘medium’) still gives thumbnail-size img
- How to update custom image sizes?
- Attachment Image using wrong src?
- Create an instance of add_image_size
- custom image size not being fetched
- Thumbnails are hard cropped not matter what
- Featured image size always cropped bottom
- Using the_post_thumbnail do not rollback to original image if specified thumbnail does not exist
- Missing image size
- Post thumbnail not displaying correct size
- Making a ‘featured image’ become the image for a full banner (top of page) image in a blog post?
- wp_get_attachment_image_src() works on index, but not on Archives
- Featured Image, and Image in post
- Setting featured image based on related post
- Trouble Retrieving Thumbnail URL on Front-Page
- Always generate thumbnail after sideloading image