My hosting company ran some updates on my server. After the updates I got errors attempting to upload images through WordPress and Joomla sites on my server. The error I received on WordPress was an HTTP error in red text. In Joomla it would actually kick me out to an Internal Server Error similar to a 404 Not Found page. It was pretty frustrating. I contacted my hosting provider and they did some looking around. I actually came across the fix on my own and made the change I describe below. I was able to do this because I have a dedicated server. If you do not have a dedicated server, you will have to ask your hosting provider to change this for you.
I opened up Terminal on my Mac and navigated to the Apache Config folder. With in that folder is a securities file named modsec2. Within that file Flash was blocked. In WordPress and Joomla flash is used for the image uploading script.
Navigate to this file:
I simply commented out the following by placing a # in front of it.
##SecRule REQUEST_URI “/usr/local/flash”
After you make that change, restart Apache and give it a try. There is one other fix that I used to have to add in older versions of Joomla. I thought I would mention it as another option if you still have the same errors.
In your .htaccess file that is located in the root directory of your website you can add the following.
Hope this helps!