Panorama can hold up to a maximum of 64 images. To configure the number of images from the CLI, using the following command:
> set max-num-images count x ( x can be any number between 2 to 64)
Prior to PAN-OS 6.0:
The Software Deployment tab in Panorama does not hold more than 5 downloaded images.
The Software Deployment tab will not hold more than a maximum of 5 downloaded images at any point. As soon as the 6th image is downloaded, the oldest image will be deleted automatically. As shown in the screenshot below.