Updating hosted images, Making images that have been replaced using the same name update Options

[SMMorse4]

I work for a business that hosts images we use for our website and email campaigns on our domain. We've recently revamped most of our images across all platforms, and to make the new images appear when someone opens an older email, we replaced some images(mostly icons and logos) using the same file names. Unfortunately, we've had varying levels of success with this, with some emails displaying the new images while others still displaying the old versions of the images, and even new emails I've coded displaying the old images.

Does anyone know how to force all code that is using images from our repository to display the current versions of the images?