Set maximum upload size for avatars and cover images

It is recommended that you limit the size of the images that your members are able to upload onto your website. In this way you can prevent your users from wasting disk space on your server. 

In order to set a size limit, add the following line to your theme's functions.php file, or to your wp-config.php file.

// Set the avatar image max size
define( 'WPUM_MAX_AVATAR_SIZE', 10240 );

// Set the cover image max size
define( 'WPUM_MAX_COVER_SIZE', 5242880 );

The above example will set the maximum file size for avatars to 10kb and cover images to5MB. The WPUM_MAX_AVATAR_SIZE and WPUM_MAX_COVER_SIZE constants only accept bytes as a value.

Sizes examples:

50kb = 51200

100kb = 102400

1mb = 1048576

You can use a website like this to help you calculate the any size you want  http://www.whatsabyte.com/P1/byteconverter.htm