Hi Andrew, thank you for your question.
Are you having trouble inserting images that already exist in your Media Library or are you trying to upload new images into your page content?
If the problem is happening with new images then it might be related to this issue from the WordPress.org forums. In that thread a user created a plugin that addresses the WordPress bug and should allow you to upload new images and get past the ‘file too large’ error message.
I hope that helps you get your images working as expected and please let us know if there is anything else that we can do to assist you.