Applying format painter reduces clarity of images

Hi, all.

I'm wanting to apply the format of a high-resolution photo with a rounded border and a shadow to other photos and graphics.

The goal is to retain the full resolution of the item the format painter is applied to.

After some experimenting, I've found that I need to apply the formatting of photo > photo, and graphic > graphic.

Applying a photo's format to a graphic makes it fuzzier...in some instances.

The resolution and size of the photo I'm using for the format is much higher than the photos it's applied to, yet sometimes the resulting photo's clarity is reduced.

I can't seem to find any logic to this.

Is there something I'm missing, or is there another way for me to accomplish this?

Thanks!