BirdID is 0.

In form view, the Bird ID changes approriately in both the form and the subform as per this photo.

Your subform is going to a new record.
Have you set Link Master Fields / Link Child Fields?

Hi Kevin. They are both set to BirdID

In photo 3, it shows the folder in which the photos are saved. But in Photo 4, it is not showing the folder and hence no photos.

Subform going to new record - no images to display

You need to find out why the subform is going to a new record if there is a corresponding record.

When you set BirdID, are you Requerying the Subform?

Ok. I see what you mean now. Thank you. Will try and adjust this.

Thank you Kevin. All working now - a simple mistake but now corrected.

Great. Happy to help.