I'm also facing this problem.
I have an online printing site where I need to collect high resolution image file (higher than 10MB) from customers. However, I can only upload image file less than 8MB currently. The website is hosted on iPage.
I have updated the upload_max_filesize to 20MB in php.ini and Preference in the backend. However, when I try to upload a 10MB image file, the website shows me this error.
According to iPage's technical support, it was due to script execution time. The script execution time is 120s. I have updated max_execution_time, but there is no effect. The technical support told me that "it is not possible to increase the script execution time as ours is a shared hosting environment."
May I know is there any other solution? or which hosting do not has this limit?