Default Still Image Length Same As Default Layer Length in 18.4.1? Bizarre!

I have been travelling and collecting still and video footage for a large project since May 2021. I'm just using this updated version (18.4.1) of After Effects. I notice in PREFERENCES that I cannot independently set the default lengths of a new layer and of stills added to a composition. I want my new layers to be the length of my composition, but not my still images. Why did Adobe do this?