If all images are linked it should not affect your db file size - because they're not embedded or stored in a table. When you set a picture property for a command button or image control, just be sure to link rather than embed. IMO, it makes the most sense to have an image folder as a subfolder to the folder containing the db. Then you can store the image path as a relative path and everything (image linking-wise) should be OK no matter where the db folder and its subfolder(s) is kept. There is a CurrentProject.Path property that identifies where the project is stored, so all you have to do is add the image subfolder path to that path.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.