If you receive '404' or 'Page not found' errors after submitting a review with picture(s) on a WooCommerce product page, the problem is most likely related to the configuration of your web server. To confirm it, please submit a test review with a very small picture (less than 5 KB size). If it works, then the problem is definitely caused by size limits for uploaded files configured on your web server.
Different hosting providers set up different rules and limits for upload of images. You can try to adjust the upload limits yourself by editing your .htaccess file. Please remember to create a full backup before making changes. For example, try to add the following code:
<Files *.php> SetInputFilter PHP LimitRequestBody 5242880 </Files>
It tells Apache to allow up to 5 MB to be uploaded to the server.
If it doesn’t help, please contact your hosting support. If the hosting support cannot help you, please use media upload feature on aggregated review forms. They are hosted on AWS (Amazon Web Services) and will enable you to overcome file upload limits of your server.