The Multi-View option in the Image to 3D panel allows you to upload up to 4 images to contribute to your model generation.
In Image to 3D, click on the Multi-View toggle:
From there, you can upload up to 3 more images from your initial image upload. It does not matter the order of images that you upload. Additionally, it is best to not include multiple views and/or objects in the same image.
Note: this feature is only available for Pro and Studio plans.