I am uploading images that are automatically inserted into a block. It appears as an Image Library on the page.

This was created by a web designer years ago. When I try to upload new images it allows me to create it, but then I can't view the images (I get the box with the red X on it). I viewed the "inspect element" option on Google Chrome and received a few error messages regarding JavaScript, but I'm unfamiliar with what it means.

Error messages:
Uncaught ReferenceError: jQuery is not defined
Uncaught ReferenceError: jQuery is not defined
Uncaught ReferenceError: $ is not defined.

I followed the web designer's instructions on uploading images and the file sizes are the same as the previous images uploaded. Any idea what's wrong and how to fix it?

Thank you!!!