A mosaic I made using the Raster Functions>Mosaic Rasters only shows half of the images
Heres all the aerial photos I have
Here's what's being shown
All photos were included, I don't know those ones aren't showing up
This ArcGIS Pro Esri Community post may provide some possible solutions/insights into what's happening - Solved: Rasters won't display after being added to mosaic ... - Esri Community
As a true mosaic datasets vs. a function, I know you can go into the Catalog Pane, and in the geodatabase that the mosaic is stored in, right-click on it and choose properties. From the Mosaic Dataset Properties, click Default and change the "Maximum Number of Rasters Per Mosaic" from the current value to say 100 or more. Then you'd see all the images.