Is there a functionality in the Story Map Editor that allows me to change image size once I have uploaded it from my computer?

[ConnorJopson]

My image is too large but I would like to keep the resolution and make the image smaller size in the actual story map presentation.

[RupertEssinger]

In order to answer your question, we need to know which Story Map app you are using. There are several . Each one has its own Editor:
Apps | Story Maps