The main failure patterns #
WordPress media upload failures fall into a few distinct categories: the upload fails immediately with a specific error message (a file size limit or a permission error), the upload appears to succeed but the image never appears or won’t process (thumbnail generation fails), or the upload produces a vague “HTTP error” with no further explanation. Each points to a different underlying cause.
File too large: the 413 error and upload size limits #
If you see “413 Request Entity Too Large” or a message saying the file exceeds the maximum upload size, the fix is increasing the upload limits in your server configuration. There are 3 PHP values that control upload size, and all 3 need to be set higher than the file you’re trying to upload: upload_max_filesize, post_max_size, and memory_limit.
The easiest path: contact your hosting provider and ask them to increase the PHP upload limit. Most hosting control panels also include a PHP settings area where you can change these values yourself. The limit shown on your Media > Add New page (WordPress displays the maximum upload size) reflects the lowest of these 3 values, so all 3 need to exceed your file size.
HTTP error with no further explanation #
The generic “HTTP error” during upload is one of the more frustrating WordPress messages because it names nothing specific. Run a Loupely diagnosis immediately after the failed upload while still on the Media Library page. The PHP error capture will often contain the actual error: a memory exhaustion during thumbnail processing, a permission error writing to the uploads directory, or a plugin conflict during the upload hook.
If Loupely identifies a PHP Fatal Error pointing to a specific plugin, deactivating that plugin and retrying the upload is the next step. Image processing plugins (compression, optimization, WebP conversion) are common sources of upload conflicts.
Upload succeeds but images won’t process #
The file uploads but WordPress can’t generate thumbnails, or the image shows as a broken file. This is almost always a server-side image processing issue. WordPress uses either the GD library or ImageMagick to process images, and if neither is available or properly configured, image processing fails silently.
Check Tools > Site Health > Info > Media Handling to see which image processing library WordPress has available. If both show as unavailable or if there are warnings, contact your hosting provider. They control which PHP extensions are installed at the server level.
Permission error on the uploads directory #
WordPress writes uploaded files to wp-content/uploads/. If that directory or subdirectories have incorrect file permissions, uploads fail with a permission error. The correct permissions are 755 for directories and 644 for files. Your hosting file manager or FTP client can set these. Some hosting providers include a “reset file permissions” tool in their control panel that handles this in one step.