If the image uploads (both the single image and the multi-image uploads) start giving http errors when you try to upload images to the media library, please follow the steps below in order to troubleshoot the issue:
Step 1: Try to activate the default theme. If this resolves the issue, reach out to your hosting company and follow step 2. If you still experience the same issue, please go to step 3.
Step 2: Please ask your hosting provider to increase the max execution time for this site to minimum 60 - 100 sec. Ordinary the uploads fail because the request times out while the thumbnails are being created. WordPress generates all registered thumbnails when you upload the image, and since this theme uses a number of different sizes it takes more time to generate the thumbnails than it takes when you use the default theme. This would explain why the issue disappears when you switch the theme.
Recommended PHP configuration limits are as follows:
You can verify your PHP configuration limits by installing a simple plugin called WordPress phpinfo.
Step 3: Check if the wp-content/uploads/ rights are set to 777
The theme and plugins require PHP version 7.0 or higher. Now is the time to think about upgrading to PHP 7.0 if you haven’t already. Not only because you want to be running on supported software, but you are guaranteed performance benefits! If your current WordPress host doesn’t support PHP 7.0 yet, we strongly encourage you to seek out new hosting.