Hook for validating and rejecting frontend image upload

I found it after trying with several hooks.

Use ‘init’ and check if $_FILES is empty, if not, do what you want to do.

init hook

Related Posts:

  1. Hook to get image filename when it is uploaded
  2. How can I add an image upload field directly to a custom write panel?
  3. Hook event for upload image in the menu
  4. Is there a better way to implement responsive images than what WordPress uses by default?
  5. What filter should I use to insert a button inside on Media>Add New
  6. Upload multiple images and insert them into custom html code
  7. Cleaning a filename after image sideloading a url that contains `%20`
  8. How to move an image in a plugin to the upload directory and make it as a media of wordpress?
  9. WordPress discards PNG file when uploading plugin file
  10. Is it possible to convert various image types from remote URLs to WebP and then serve them immediately?
  11. Using “add_image_size” to register custom image sizes inside plugins not working
  12. Leveraging Core Functionality in Icon Upload Plugin [closed]
  13. Upload to a specific media folder created by FileBird Lite
  14. Standard location for plugin to save/cache files?
  15. Add a new tab to WordPress Plugin install Listing
  16. Admin settings update updating every time home page is hit?
  17. Global Objects and Public Methods
  18. How do you use the plugin boilerplate loader class to hook actions and filters?
  19. How Do I Load My Action Earlier Enough?
  20. Does WP fire delete_post when trashed posts are automatically deleted?
  21. How to catch images with blank dimensions?
  22. Saving the pre-sanitized filename of an attachment as the Title or Caption
  23. Why does do_action pass a blank string as the first parameter if no $arg is set?
  24. How to add a link to WordPress Plugin install Listing
  25. I can’t find where a hook is being defined in a plugin – Easy Digital Downloads
  26. Call activation hook multiple times
  27. Having Problem On Getting WP Post Gallery Images URL
  28. Two-step login process – Is it possible?
  29. Set first image (external) as featured image / thumbnail
  30. How can I hook into existing WordPress Bulk actions?
  31. Hook for post permalink update
  32. Get returned variable from a function to add_shortcode function
  33. WordPress Media mime type filter problem 4.0
  34. How can I add a custom meta value on file upload?
  35. How to get an image transferred via FTP or script to appear in Media Manager?
  36. Earliest WP Hook to Safely and Reliably Redirect
  37. Define a function outside a class and call the function using action or filter hook
  38. Can I differentiate between “Delete Post Permanently” and “Empty Trash” and do something for each accordingly?
  39. Synchronize Custom post type tags to WordPress default posts tags
  40. Using the component outside the editor. select(‘core’) is null
  41. comment_email hook doesn’t seem to work for comment editor field
  42. unable to stop loop when using wp_insert_post with publish_post hook
  43. Hook into theme-switching later than `setup_theme`
  44. Save image as featured image
  45. How to rename image at uploading on specific plugin or post-type in WordPress
  46. Is it possible to delay execution of shortcode output callback?
  47. WordPress Ajax callback function from plugin – OOP
  48. Why my database table not created on activation?
  49. How to send email in wordpress with more than one attachments
  50. Act on user meta updated, but only once
  51. Adding Attachment Display Settings in custom media frame
  52. Resizing Images for a Gallery-Plugin?
  53. Is there any way to allow a plugin to write over a previous version?
  54. Files automatically added
  55. best practice for query string values – get_query_var always empty for my value supplied in query string
  56. get_current_screen() return null
  57. How to replicate Media Library “Add New” on Plugin Settings Page
  58. Plugin writing: access file that was just uploaded
  59. Modifying meta tags after doing ajax call in plugin
  60. how to add custom functionality after woocommerce place order button
  61. Where to add hooks in a class
  62. How to use output buffering in WordPress hooked functions?
  63. Conditional hook based on the core function that is calling it
  64. Adding option to Gallery shortcode
  65. Get attachments from a post
  66. I have 2 plugins using the same wp_login action hook and one is not working
  67. How dynamic action login_form_{action} is working
  68. How to get all queries’s results after they have executed?
  69. flush rewrite rules after plugin update?
  70. Odd map_meta_cap $args on post edit — sometimes integer, sometimes string
  71. How can I create a custom plugin that allows anonymous users to signup without registering?
  72. hook filter after the_content on a specific page
  73. Associate multiple email addresses with the same user account, so they can log in with either
  74. Run command “composer install” when activating wordpress plugin
  75. Custom filter not working
  76. Configure WordPress to Generate Scheme-less Relative URLs
  77. How to submit/upload data to database and in specific folder?
  78. Get audio metadata on file upload
  79. Ajax +wordpress onClick link redirect to new page and create html content
  80. How to replace settings in WordPress plugin from a theme
  81. Creating posts with links from a txt file
  82. The URL of images on my website changed after being set as featured image
  83. apply_filters() and call_user_func() to define and call a function outside a class
  84. WordPress Favicon not Working For Images/Videos/PDFs
  85. what functions to use to resize images and create DB metadata for them after/during upload?
  86. Plugin Development – Call to undefined function comment_exists()
  87. Prevent plugin activation and add admin notice
  88. How to destroy or dispose wordpress uploder/manager?
  89. Does WordPress have something like timer hook?
  90. Can I use a hook other than ‘init’ to handle form submissions?
  91. Template file structure , wordpress hook for altering the template
  92. Changing upload directory for plugin uploads only
  93. How do I replace title with my plugin?
  94. Looking for Hook that is fired after a plugin or wp upgrade is installed/updated
  95. Woocommerce: block user removing cart item
  96. How can I get a plugin to hook ‘dbdelta_queries’ — a filter used during version update?
  97. Send retrieve password notification email with custom HTML email template
  98. Add a custom image source
  99. Ninja Forms: Front-End Forms, Post ID?
  100. upload image to wordpress media library failed for custom post type