“Upload_max_filesize”, is a hosting issue, not the theme issue, which can be easily fixed. I would kindly request you to contact your Hosting Service Provider about the issue. They will surely fix the issue.

You can refer to below links as well for the fix.

• http://www.wpbeginner.com/wp-tutorials/how-to-increase-the-maximum-file-upload-size-in-wordpress/
• https://wordpress.org/support/topic/tthe-uploaded-file-exceeds-the-upload_max_filesize-directive-in-phpini/

Please ensure that your hosting service provides the features recommended by WordPress. If you are looking for better WordPress hosting, check out this review of best WordPress hosting providers.