the_post_thumbnail(‘medium’) setting some images width=1 height=1

It’s only a guess, but it’s also most probable cause…

When you upload an image to WP, some metadata is generated and stored in database. This metadata contains such info like name, path and size of the image (to be more precise – paths and sizes of all created images based on uploaded one). And… This metadata is stored as serialized array.

When the metadata is corrupted (so WP is not able to unserialize it), it can cause images with size 1×1 (WP doesn’t know what is the size of given image).

What should you do in such case?

It’s easy to correct this. All you need to do is to regenerate metadata for these images. (There are many plugins which will help you with this – look for “regenerate thumbnails” or “rebuild” thumbnails”).

Related Posts:

  1. Filter to remove image dimension attributes?
  2. Stop wordpress from hardcoding img width and height attributes
  3. How to automatically add rounded corners to thumbnails?
  4. WordPress adding scaled images that don’t exist (1536×1536 and 2048×2048)
  5. How to change image type for specific size?
  6. Is there a hook which fires after all thumbnails are generated?
  7. Featured image shortcode
  8. How to find attachment by it’s name?
  9. Cropped featured image replaces original image in gallery
  10. Image Scaling using get_the_post_thumbnail issue in WordPress
  11. Remove title attribute from images
  12. Insert an image into a post by API
  13. How to create thumbnails with a fixed width, so all of them will have the same width?
  14. How to limit number of images being printer out in “Set Featured Image” pop up?
  15. Black and White thumbnails
  16. How can I add the “Use as featured image” to a custom metabox?
  17. Double thumbnails?
  18. No srcset for hard-cropped thumbnails
  19. How to output placeholder image if no featured image set?
  20. Featured Images on Front Page
  21. Download button for Featured Image in every post – automatically
  22. Removing Title Tag from Thumbnails
  23. Show prev and next post links for parent post of current image in attachment page?
  24. Add a featured image in my theme?
  25. Get original image from thumbnail URL
  26. Featured Image .svg height and width 1px only
  27. How to check if user is uploading/setting an image as a featured image?
  28. Images are randomly deleted from server
  29. attach unattached featured images to respective posts
  30. WordPress reduces the full size image and uses it as the original
  31. Thumbnails are bigger in size than the original image
  32. Remove image classes from post thumbnail output
  33. Lazyload post thumbnails
  34. Exclude featured image from gallery in wp-admin
  35. SVG Featured image not shown in twitter
  36. Featured images not displaying at full resolution
  37. WordPress crops images differently on retina screens?
  38. Big Image on Featured Post, Normal on Single Post
  39. offload media to external services [closed]
  40. Update old Post image metadata to ‘thumbnail’ wp_attached_file
  41. How to stop wordpress always displaying full-res images
  42. WP keeps looking up post thumbnail on https even though wp-config says http
  43. Images stopped loadding after adding SSl
  44. WordPress PNG compression issue
  45. How to replace images?
  46. Fixing image names for a site being restored
  47. Setup Featured image on all posts from thesis thesis_post_image custom field?
  48. Export xml use/import images from theme directory
  49. Get custom thumbnail sizes [duplicate]
  50. Should I not compress my jpeg files before uploading to avoid double compression?
  51. Custom responsive ‘featured image’ sizes
  52. Generating a certain sized thumbnail on the fly?
  53. How do you import images from a URL in your post?
  54. How to set uploaded image as featured image wordpress
  55. What can i do add title to ‘large’ image?
  56. Retrieve Image Attachments Getting Post Thumbnail Image First
  57. Height and width attribute not setting by the_post_thumbnail
  58. add_image_size function not working
  59. How to force WordPress to upscale images?
  60. Why doesn’t WordPress use the smaller sized image?
  61. What sense makes medium_large_size_h => 0?
  62. How to set minimum required size for featured image?
  63. All Images not calling alt text
  64. How do I link a featured photo to it’s post?
  65. Can we use featured image as third party website image URL
  66. Is it possible to enable the ‘Link To’ field under ‘Attachment Display Settings’ for a Featured Image?
  67. Show (print) featured image all dimensions (height, width)
  68. Use default image as var
  69. add_image_size not working
  70. Serve different images per screen size and cache possible?
  71. Product Images Low Quality After Updating From WP 3.5 to 4 [closed]
  72. Placing a featured image into header
  73. Convert featured images into “product images”
  74. How to add thumbnails to posts and pages automatically in a uniformed fixed elegant way?
  75. Resize uploaded images [duplicate]
  76. How do I display the featured image from an image gallery using a reference in code? (example within)
  77. How to use the thumbnail size with catch_that_image
  78. Using different size thumbnails on different parts of my site… with functions.php?
  79. Thumbnail and image management
  80. attach several images to post + gallery
  81. my featured image of wordpress are not showing in the front end though image are uploaded in media library
  82. How to change Gallery image url in product page ? In function.php?
  83. How is called this thumbnail slider feature
  84. Custom image size not displaying with wp_get_attachment_image()
  85. How to echo images Urls from a wordpress post, that are relally in the post
  86. How to delete original image file after upload and resize
  87. An error has occurred during the upload process in wordpress version 5.3.2
  88. Force WordPress to always generate a thumbnail for original image
  89. Show featured image in all posts
  90. Get post thumbnail in specific size
  91. featured image in custom poste type (backend)
  92. Custom Background for each page and post
  93. stop wordpress from resizing feature gif images
  94. Using custom field to change alt text for a featured image
  95. How to display image thumbnails on the search results page?
  96. Declare global variable that can be used on other function
  97. Get custom size of thumbnails
  98. Black and White Thumbnail in WordPress Gallery
  99. Getting top Image From the Gallery and printing out a thumbnail with Exact Dimensions
  100. How can I use an image from an external source without uploading it to the media library