Quick question which uses less system resources:

1 x 178/24 image
1 x 178/36 image
1 x 178/48 image
1 x 178/60 image
1 x 178/72 image

OR

5 x 178/1 image stretched to 24/36/48/60/72 sizes?

The latter might take a few CPU cycles to stretch the image, but it would be the more elegant IMO since you don't have to have so many variations of the same image to waste file space.

In the end you still display a graphic at the same size, so I don't think there's any difference.

physical memory storage will be the same no matter how you do it. Hard drive space will be better with 1 stretched image in PNG format...but that will up your CPU resources.