This is really an upload limit issue.
- Log into cPanel.
- Find the Software section and click on MultiPHP INI Editor.
If you don’t have the MultiPHP INI Editor but do have the PHP Configuration tool, you can skip to the “If you don’t have the MultiPHP INI Editor” section.
- In the dropdown, select the domain for which you wish to change the maximum upload size.
- Find the following values and set them accordingly:
upload_max_filesize = 64M post_max_size = 64M memory_limit = 90 file_uploads = Enabled
- Click Apply to save your changes.
After these changes go back to Media > New and see if limit has increased from the auto 2MB
Upload your new theme