Locate and open the php.ini file of your site in a plain-text editor such as Notepad, and change the following parameter: memory_limit = 128M ; Maximum amount of memory a script may consume (128 Megabytes) A value of 128M (128 Megabytes) will work for most scenarios, however a high-load site might require more.
Upload errors or large files can be caused by a restriction on the PHP configuration in the web server.
Edit the php.ini (you might need help from your hosting company) file of your system and look for the following parameter: upload_max_filesize Edit it to a value that works for the size of the files you want to upload, for example: upload_max_filesize = 64M This will enable upload of files up to 64 megabytes in size.
Post_max Edit it to a value that works for the size, for example: upload_max_filesize = 32M Once updated, restart your Web server to put the change in action. Note: Some hosting companies do not allow direct access to the php.ini file or server restart, please consult your Hosting support on how to perform this change.