php limit upload_max_filesize is set to 2 MB on our servers, what means you can upload files up to 2 MB in size via your websites.
Also, we have a file size limit of 5MB when uploading files via the file manager in cPanel. Currently, This limit can not be increased anymore.
If you have bigger files to upload, you need to upload them using FTP, where no file size limits are applied (except for the account size limit).
You are also welcome to upgrade your account to premium, where you will be able to upload files up to 128 MB via PHP, and files of unlimited size via the cPanel and FTP and also unlimited disk space for your website! You can upgrade your account at http://www.000webhost.com/upgrade