Error message w Plug-in for pics (size 5-7MB) using Thesis theme

Hi, I am a beginner with wordpress. I hired someone to create our website and would like to update and maintain it myself. I just uploaded some pictures to the Media Library but I am receiving an error message saying it can't "smush" them because each pic is over 1MB- the limit for Yahoo?? (each pic is about 5 to 7MB). Now I am stuck. Do I need a new plug-in? If so which one? Can it work with the current Yahoo one or do I have to uninstall the current one? I am completely new to this. Thank you so much for any help.