You are on a good track.
- You first define your thumbnail sizes in your functions.php
- Make you upload big high-quality images but still good enough for the web
- You then need to regenerate your thumbnail, I recommend this plugin: https://wordpress.org/plugins/regenerate-thumbnails/
- In you new code, you need to call your desired thumbnail based on the size you have provided, e.g.
<?php get_the_post_thumbnail( $post_id, 'my-slider-img' ); ?>
Related Posts:
- Missing feature image link function
- Automatically set the featured image
- Get recent posts with thumbnail
- How to display the_post_thumbnail if a post has one or otherwise display the first image in a post?
- Add options to featured image
- Linking thumbnail to full size image
- Generating Responsive Background Image Sizes in PHP
- Why are image thumbnails cropped proportionally (not per dimensions)?
- Add a Post Thumbnail to an RSS Feed with custom size
- Make WordPress size and name images for Retina.js
- Why are image thumbnails cropped proportionally (not per dimensions)?
- the_post_thumbnail fallback using hooks
- Display height and width properties with the_post_thumbnail() or related function
- Setting featured image with function, 1 part not working
- Removing the first image in content
- How to set the jpg image compression for specific thumbnail sizes?
- Function to auto-set a featured image that is already in use
- img width and height attributes being set by get_the_post_thumbnail
- Get the 5 lastest Featured Posts from a category
- How to display a default image for post thumbnail using functions.php?
- Change size and crop medium_large images
- Getting Featured Image Caption to Only Show if Populated
- wp_get_attachment_image function size argument not working if I also add a custom class
- Can’t check if a post has thumbnail adding filter to get_post_metadata()
- Add Featured image column into wordpress admin on pages AND posts
- Post thumbnail not showing in WP admin area for custom post type
- Overwriting Parent Theme’s Image Sizes
- Backstretch.js and thumbnail sizes to reduce loading time
- set_post_thumbnail when user is not logged in
- How to stop twenty fifteen theme from cropping featured images?
- Can you put a condition on add_image_size() depending on the width of the uploaded image?
- show first 3 thumbnails of posts in different sizes [closed]
- Set spesific size of featured images
- Can’t generate thumbnail images
- It does not work concatenation in function.php
- How to retrieve the current post’s generated featured image size?
- Check if the image size is available and if not use ‘full’ image size
- is there a way to remove featured image from blog page and single page
- How to hide image-url if no attachment?
- Can set_post_thumbnail be used to remove a thumbnail?
- Can’t locate custom image sizes defined by child theme
- How to add a new image size and apply it to posts only?
- Show Featured Image in else statement
- Change custom featured image size in twentythirteen child theme
- resizing of thumbnails not working
- Featured Image keeps cropping
- show all the posts thumbnails
- struggling with syntax for the_post_thumbnail();
- include w_thumbnail_src in function?
- Custom image sizes showing in Classic Editor only when upladed directly to post
- Which filter fires upon setting a featured image
- Can I use ‘Featured Image’ as a hero image and a thumbnail?
- remove_filter function to unhook twentysixteen parent theme function
- Can You Set A Minimum Image Dimension For Resizing Images?
- Featured image on archive page based on post type
- Printing medium sized image
- Sticky – Featured Image
- Frontend Feature image upload not work
- Best way to add image to recent posts widget?
- Remove Featured Images from Posts Older Than a Certain Date
- Apply height and width for the_content() inside youtube video tag
- Set thumbnail from URL, by grabbing image in functions.php
- add_theme_support not outputting thumbnails
- WP supersize not displaying when different languages flags are selected
- Full size image option removing problem
- Image width issue in IE [closed]
- image_size with respect to aspect ratios
- Is mytheme_post_thumbnails() still necessary?
- deregister scripts on certain page
- Using get_terms for custom taxonomy in functions.php
- Editing or filtering the output of the Genesis navigation
- is_plugin_active() not properly returning true
- Display gallery on top before content
- Move Post to different category if post_meta field is 0 or is 2 days old?
- Excerpts are not displayed by a shortcode on category pages
- Condition OR for current user ID
- Retrieve a value from Yoast SEO to use to set a default twitter card image honoring overrides
- Adding javascript to functions.php causes problems with my template
- Where do I store custom functions that call custom page template files?
- How to Extend login session times to a Month
- How to add array [closed]
- How add body_class from wp_termmeta
- remove_action not working, even after changing priority [duplicate]
- Theme Customizer – Custom Sections Display, but do Nothing
- wp enqueue style on about us page
- CF7 select value get to function and reciept value from function
- Remove nofollow from internal comment links via functions.php
- How can I automatically delete comments that contain a URL?
- Run function for specific user only
- Conditionally apply css for a specific template part
- Setting Active Nav item (of Pages) when you are on a Post with Category
- How to disable site title and description when custom header is uploaded on the customizer?
- Register a widget area when a theme option has been saved?
- Blank child theme – functions.php problem
- Overwriting a Shortcode
- Hiding Google Analytics code based on theme options
- Text before price on WooCom
- Warning: call_user_func_array() expects parameter 1 to be a valid callback
- Change Post status based on custom field date +1 day
- How to store page-{id}.php templates in custom folder