HTTP Error when uploading files above 7mb unless using GD Image Editor

I sometimes get this exact same issue and set of symptoms.

It’s caused by the image being too large for the memory available. Not the file size as that has compressed data, but the actual width x height x colourdepth.

You can see the full size image because it uploaded fine. You have trouble in the media browser because WP ran out of memory while scaling and cropping the image and so there is no version available for the media browser thumbnail.

I’ve always found that allocating much more memory to the process fixes it. Or use smaller images (dimensions, not file size).

WordPress will use the higher of WP_MAX_MEMORY_LIMIT and your PHP memory limit, so as long as your hosting allows the easiest thing to do is to set WP_MAX_MEMORY_LIMIT in your wp-config.php:

define( 'WP_MAX_MEMORY_LIMIT', '257M' ); // you choose how much

The default is 256M for image handling anyway, so if you have problems resizing images it’ll need to be something higher than 256M.

As long as your host allows PHP to increase the memory using @ini_set then this will work.